Tag Archives: May weather

Weather History

May 9 to May 15: This week in Denver weather history

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This Week in Denver Weather History

As we get further into spring our look back at Denver weather history begins to show more typical severe weather.  This week in Denver weather history we see plenty of hail, heavy rainfall, a tornado or two and lightning that caused serious injuries.

8-9

In 1957…intense heavy rain caused flash flooding on toll gate creek in Aurora where 3 people were killed in a car. Up to 4 inches of rain fell in 5 hours in the Toll Gate Creek basin.  The rain also caused flash flooding on Sand Creek in Aurora and Denver.  Rainfall totaled 3.29 inches at Stapleton Airport with most of the rain…2.34 inches… Occurring on the 9th.

8-10

In 1979…4.3 inches of snow fell at Stapleton International Airport where northwest winds gusted to 30 mph on the 8th. Most of the snowfall…2.3 inches…occurred on the 9th. High temperature of only 35 degrees on the 9th equaled the record low maximum for the date.

9

In 1875…a heavy windstorm swept across the city for most of the day.  West-northwest winds averaged a sustained speed of 31 mph between 6:00 am and 3:00 pm.  The peak wind was sustained to 45 mph at 9:50 am.

In 1918…post-frontal winds were sustained to 40 mph with gusts as high as 43 mph.  Only a trace of rain fell.

In 1941…a tornado was noted at 2:20 pm to the northeast of downtown and was followed by another similar shaped cloud or dust roll estimated 3 miles behind.  Thick dust followed with heavy gusts of wind.  The temperature fell 15 degrees in 10 minutes following the twister.  The mild tornado did little damage except to unprotected frame structures.  Winds were sustained to 50 mph with the passing of the tornado at Stapleton Airport.  It was visible to observers for 10 minutes and was lost from sight as it traveled east into huge rolls of dust.  Hail and rain followed with a few hailstones as large as 1/2 inch in diameter downtown.  No damage was reported from the hail.  Thunderstorm winds sustained to 31 mph produced blowing dust downtown.  Precipitation was only 0.07 inch.

In 1983…streams swollen by recent rain and snowmelt caused an earthen dam to collapse…washing out portions of State Highway 67 near Deckers in southern Douglas County.

In 1992…three boys…ages 11…12…and 16…were struck by lightning while taking cover under a large tree during a thunderstorm in Jefferson County…just 7 miles northwest of Denver.  The three were seriously injured.

9-10

In 1889…heavy rainfall totaled 2.15 inches in downtown Denver.  The cold rain was mixed with snow at times overnight.  Temperatures on the 10th ranged from a high of 38 degrees to a low of 32 degrees with north winds sustained to 22 mph.

In 2003…a late spring snowstorm hammered the mountains… Eastern foothills…and urban corridor.  The heaviest snowfall occurred north of interstate 70.  The heavy wet snow caused damage to trees throughout metro Denver and downed power lines.  About 40 thousand people along the urban corridor were without power.  Storm total snowfall amounts included:  11.5 inches in Louisville… 8 inches in Boulder and Broomfield; 7 inches in Thornton…Broomfield…at Denver International Airport… And at the site of the former Stapleton International Airport; and 6 inches 4 miles east of Denver.  Snowfall ranged from 4 to 9 inches across extreme southern weld County.  In the foothills…15 inches of snow fell near Jamestown…9 inches at Rollinsville and Rawah…with 8 inches at Chief Hosa and atop Lookout Mountain. The snow was accompanied by thunder on the afternoon of the 9th at Denver International Airport where west winds gusted to 25 mph on the 9th and north winds gusted to 22 mph on the 10th.

In 2015…from the 9th to the 10th…a strong storm system brought heavy snow to areas in and around Denver. Moderate to heavy rain showers transitioned over to snow by early in the evening on the 9th. Heavy wet snow overnight caused many trees to break under the pressure of the sudden weight. Tree damage ranged from minor to significant…with old growth trees losing large limbs and new trees sustaining fatal damage. Power outages affected about 43350 Xcel Energy customers in metro Denver. The Intermountain Rural Electric Association also reported about 1000 power outages in the Strasburg areas. In the high country…CDOT shut down Interstate 70 between the Eisenhower Tunnel and Silverthorne due to multiple crashes.

10

In 1875…a windstorm sand-blasted the city from 10:00 am until midnight.  Northwest winds sustained to 60 mph brought clouds of sand…which caused high damage to unfinished buildings.

In 1912…a vigorous cold front produced strong north winds and rain.  North winds were sustained to 48 mph with gusts as high as 60 mph.  Rainfall totaled 1.10 inch.

In 1935…no precipitation occurred…making this one of only two days without precipitation during the entire month.  The other day was the 21st.  Precipitation totaled 4.95 inches for the month.

In 1956…northwest winds gusted to 53 mph at Stapleton Airport where the visibility was briefly reduced to 1/2 mile in blowing dust.

In 1974…strong winds caused 30 thousand dollars in damage to a building under construction in Lakewood.  Microburst winds gusted to 46 mph at Stapleton International Airport.

In 1988…lightning struck a house in Boulder…setting it afire.  The house…valued at 170 thousand dollars…was a total loss.

In 1989…golf ball size hail fell over southeast Denver near the junction of I-25 and I-225.  Hail to 3/4 inch in diameter fell over southeast Aurora.  Only 3/8 inch hail fell at Stapleton International Airport.

In 1991…high winds up to 63 mph raked the eastern foothills. Winds estimated to 50 mph tore a roof from a home in Lafayette.  A tower at Jefferson County stadium in west metro Denver was blown over by the high winds.  No injuries were reported.  Southeast winds gusting to 48 mph at Stapleton International Airport produced some blowing dust.  The temperature climbed to a high of 86 degrees… Equaling the record maximum for the date.

In 2005…severe thunderstorms produced hail as large as 2 inches in diameter in and near Longmont.

10-11

In 1918…post-frontal snowfall totaled 4.7 inches in downtown Denver.  Northwest winds gusted to 19 mph on the 10th.

In 1923…winds were strong and gusty on both days.  Northwest winds were sustained to 40 mph with gusts to 44 mph on the 10th.  North winds were sustained to 39 mph with gusts to 46 mph behind an apparent cold front on the 11th.

10-12

In 2011…from the 10th to the 12th…a spring snowstorm brought heavy snow to the Front Range Foothills and Palmer Divide. Storm totals included: 18 inches…4 miles south-southeast of Pinecliffe; 16 inches in Coal Creek Canyon; 15 inches…4 miles west-southwest of Eldorado Springs; 13 inches at Gold Hill…12 inches…4 miles west-southwest of Conifer and 4 miles northwest of Elizabeth; 11.5 inches…6 miles southwest of Evergreen and 4 miles east-northeast of Nederland; 11 inches…3 miles east of Jamestown and 10.5 inches…3 miles east of Franktown and 3 miles south of Golden and 10 inches…10 miles north of Elizabeth. At Denver International Airport… 1 inch of snowfall was observed.

Continue reading May 9 to May 15: This week in Denver weather history →

Weather History

May 2 to May 8: This week in Denver weather history

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This Week in Denver Weather History

As we enter the month of May, our weather history calendar is as eventful as ever however we start to see a transition with fewer snow events and more typical spring events.  Of note are many events that caused flooding, severe winds, tornadoes, and lightning.

29-2

In 1954…a major storm dumped 10.1 inches of snowfall at Stapleton Airport.  Most of the snow…7.5 inches…fell on the 29th and 30th.  The maximum snow depth on the ground was 5 inches on the 30th due to melting.  No strong winds accompanied the storm.

1-2

In 1903…post-frontal rain changed to light snow overnight… But totaled only 2.0 inches.  This was the last snow of the season.  Northeast winds were sustained to 45 mph with gusts to 48 mph on the 1st.

1-5

In 1898…snowfall totaled 15.5 inches in downtown Denver. Most of the snow…6.2 inches…fell on the 3rd.  Most of the snow melted as it fell.  The greatest snow depth on the ground was only 2.5 inches on the 3rd at 8:00 pm. This was the only snowfall during the month.  Northeast winds were sustained to 22 mph on the 1st.

2

In 1874…strong winds upset two railroad passenger coaches near Georgetown.  The baggage was retrieved and placed in a heavy…large wagon.  The passengers then seated themselves on top of the baggage.  Another strong gust of wind upset the wagon.  The driver’s shoulder was dislocated…and a passenger’s leg was badly injured. In Denver…northwest winds increased and blew in gusts and heavy winds were observed on the ridge tops.  On the Kansas Pacific R.R. east of Denver…the wind was so strong that it blew the train back several lengths…which caused the train to be about 7 hours late arriving in the city.

In 1901…south winds were sustained to 50 mph with gusts to 60 mph from an apparent thunderstorm with hail.

In 1944…snowfall of 8.3 inches was accompanied by a thunderstorm.  This was the last snowfall of the season and the only snow of the month.  Northwest winds were sustained to 25 mph.

In 1955…southwest winds at speeds of 37 mph with gusts as high as 58 mph caused some blowing dust at Stapleton Airport.

In 1983…1 inch diameter hail fell a few miles south of Bennett.

In 1984…3/4 inch diameter hail fell in Northglenn.

In 1988…I-70 east of Denver was closed for the second straight day…this time due to snow and blowing snow producing up to 2 foot drifts.  While only 2 to 4 inches of snow fell across metro Denver…Strasburg…just east of Denver…received a foot of snow.  North winds peaked to 51 mph at Stapleton International Airport where snowfall totaled only 1.3 inches.

In 1995…lightning struck a house in Westminster sparking an attic fire.

In 2015…a sudden wind gust associated with a dissipating thunderstorm caught some flags attached to a lift and tipped it. Two men were injured when a lift at Civic Center Park in Denver fell on them during Cinco de Mayo festivities. Both men suffered from head injuries…one was in serious condition.

2-3

In 1979…heavy rain changed to snow on the 2nd.  Snowfall totaled 3.9 inches at Stapleton International Airport… Where northwest winds gusted to 26 mph.  The greatest depth of snow on the ground was only 1 inch at midday on the 2nd due to melting.  Total precipitation for the 2 days was 1.65 inches.

2-4

In 1987…a slow moving storm brought rain…wind…and snow to metro Denver.  Rainfall totaled 1.04 inches at Stapleton International Airport where north winds gusted to 48 mph on the 3rd.  The foothills received 5 to 10 inches of snow.

2-5

In 2001…a very slow moving pacific storm system became parked near the Four Corners region…which allowed heavy snow to develop above 6500 feet in the foothills with a mix of rain and snow over lower elevations of metro Denver.  Snowfall totals included:  21 inches atop Crow Hill and at Idaho Springs; 19 inches near Blackhawk; and 18 inches in Coal Creek Canyon…Genesee…and 11 miles southwest of Morrison. Snowfall totaled 6.2 inches at the site of the former Stapleton International Airport.  Precipitation (rain and melted snow) totaled 2.09 inches at Denver International Airport where north winds gusted to 30 mph on the 2nd.

3

In 1898…heavy snowfall of 6.2 inches fell over downtown Denver.  Most of the snow melted as it fell.  The greatest snow depth on the ground was 2.5 inches during the evening.

In 1907…the all-time lowest recorded temperature in the month of May…19 degrees…occurred.

In 1925…an apparent microburst produced sustained northeast winds to 44 mph with gusts to 52 mph.  Rainfall was only 0.01 inch in downtown Denver.

In 1981…lightning struck 9 golfers at the south suburban golf course.  None were injured seriously.

In 1983…hail 1 1/2 inches in diameter fell at Green Mountain west of Lakewood…with 3/4 inch stones reported in Lakewood.

In 1986…a thunderstorm wind gust to 51 mph was recorded at Stapleton International Airport.

3-5

In 1908…rain changed to snow on the evening of the 3rd and continued through the early evening of the 5th. Snowfall totaled 10.0 inches over downtown Denver. This was the last measurable snow of the season. Precipitation totaled 1.51 inches.  North winds were sustained to 23 mph on the 3rd…33 mph on the 4th…and 21 mph on the 5th.  Three temperature records were set. High temperatures of 30 degrees on the 4th and 38 degrees on the 5th were record low maximum temperatures for the dates.  The reading on the 4th was also the all-time record low maximum for the month of May.

In 2007…a slow moving pacific storm system…from the desert southwest…brought a period of unsettled weather to the region.  During the 3-day period…locally heavy snow was reported over parts of the Front Range foothills. Storm totals included:  15 inches near Conifer…14.5 inches west of Jamestown…13.5 inches; 6 miles southwest of Evergreen…and 12.5 inches at Pine Junction.  Severe thunderstorms…producing large hail…up to one inch in diameter were observed in the vicinity of Boulder and Hudson.  Lightning struck a residence in Jefferson County. The roof was hit…causing the attic to catch fire. At Denver International Airport…lightning struck a United Airlines jet as it was pushing away from the gate.  The passengers were taken off the jet and put on another plane.

Continue reading May 2 to May 8: This week in Denver weather history →

Climatology, Thornton Weather

Thornton’s May 2021 preview: From snow to severe storms

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Thornton, Colorado May 2013 weather preview.
Thornton, Colorado May 2013 weather preview.

Colorado’s famously highly variable weather seems to showcase itself during the month of May when a variety of weather conditions can be seen.

Winter-like temperatures and snow are possible as are mid-summer like temperatures or the more typical spring severe weather.

As the month starts out in 2021 we are going to enjoy unseasonably warm conditions for the first of the month then begin a period of cool, wet weather conditions. Long range forecasts portend an overall warmer than normal month with equal chances of below, at or above normal precipitation.

The month can certainly bring extremes.  Snow is not entirely uncommon during the month, oftentimes causing damage to newly bloomed trees.  More common however is severe weather, particularly in the latter half of the month.  Thunderstorms become more frequent and their associated hazards – lightning, wind, hail and tornadoes – are usual visitors.

For a complete look at what lies ahead for the month of May, check out our full preview here.

Weather History

April 25 to May 1: This week in Denver weather history

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This Week in Denver Weather History

Snow continues to be a big part of the weather we can expect this time of year as we peer back in the Denver weather history books.  However, we also see more and more occurrences of spring severe weather including hail, damaging winds, dangerous lightning and even a tornado.

23-25

In 1935…heavy wet snow fell across metro Denver.  The storm started as rain on the 23rd and changed to snow early on the morning of the 24th.  There was continuous precipitation for a period of 48 hours.  Snowfall totaled 19.0 inches over the city and 20.0 inches at Denver municipal airport.  However… Due to warm temperatures in the 30’s…much of the snow melted as it fell and did not seriously disrupt traffic. The greatest snow accumulation on the ground downtown was 12 inches…but it quickly melted.  The highest sustained wind speed recorded during the storm was 28 mph from the north on the 23rd.  The storm contained 3.16 inches of moisture.

24-25

In 1890…rain changed to snow and totaled 7.0 inches in downtown Denver.

In 1931…heavy snowfall totaled 9.3 inches over downtown Denver.  Winds were light during the storm.

In 1996…the second wind storm in less than a week developed east of the continental divide and spread over metro Denver.  High winds gusted from 60 to 90 mph.  Several power lines and poles were downed.  Some of the stronger wind gusts included:  91 mph atop Squaw Mountain west of Denver…90 mph atop Table Mesa near Boulder…85 mph in Golden Gate Canyon…and 82 mph at Wondervu.  Northwest winds gusted to 41 mph at Denver International Airport on the 25th.

24-26

In 1924…post-frontal rain changed to snow…which became heavy and totaled 10.2 inches over downtown Denver.  The greatest amount of snow on the ground was 6.0 inches on the 25th due to melting.  North winds were sustained to 38 mph with gusts to 42 mph on the 24th.

25

In 1902…northeast winds were sustained to 42 mph with gusts to 48 mph.

In 1908…north winds were sustained to 40 mph behind an apparent cold front.  Snowfall was 0.5 inch.

In 1928…rain changed to snow…which became heavy and totaled 7.4 inches in downtown Denver.  Due to melting…the maximum snow depth on the ground was 4.0 inches at 6:00 pm.  This was the last snow of the season.  Southeast winds were sustained to 19 mph with gusts to 20 mph.

In 1976…a south wind gust to 54 mph was recorded at Stapleton International Airport.  The high winds toppled a 70-foot high cottonwood tree onto the rear of house and a neighboring residence in central Denver.

In 1989…lightning caused heavy damage to a radio transmitter in Parker…knocking a Denver area radio station off the air for 3 hours.

In 1994…weather spotters reported dime-size hail at the intersection of U.S. Highway 287 and C470 in Jefferson County.  Marble-size hail covered the ground near Golden to a depth of 1 inch.  Pea-size hail was reported covering the ground to a depth of 3 inches in Arvada.

In 2016…a severe thunderstorm produced hail up to one inch in diameter near Castle Rock.

25-26

In 1985…a spring storm brought much rain and snow to metro Denver.  The foothills were buried with 15 inches of snow at conifer and 12 inches at Evergreen.  At lower elevations… An inch or more of rain fell in Denver and Boulder.  The heavy precipitation caused brief power outages in the Denver area.  Precipitation totaled 1.06 inches at Stapleton International Airport…including only 0.7 inch of snowfall.

25-27

In 1877…snow ended around 7:00 am on the morning of the 27th… After falling continuously for 48 hours and totaling an estimated 13 inches in the city.  The storm…likely accompanied by strong winds…caused trains to be delayed for 2 to 3 days.  One or two roofs of small buildings were crushed by the weight of the snow…and many tree branches were broken in the city.  There were a number of reports of livestock losses.  One stockman lost 17 horses and several cattle from the snow and cold.  Precipitation totaled 1.30 inches from the storm.

26

In 1965…while only 0.40 inch of rain fell at Stapleton International Airport…some communities in the foothills west of Denver reported over 30 inches of snow from the storm.

In 1972…a spring snow storm accompanied by thunder dumped 15.8 inches of heavy wet snow on metro Denver.  Strong northwest winds gusting to 35 mph produced blowing snow. The storm was quite intense and greatly hampered travel. High winds caused drifts 10 to 15 feet deep in some areas… Blocking roads and stranding hundreds of motorists.  An estimated 500 to 600 people were stranded in the Castle Rock area.  Rescue service was provided by heavy army equipment from Fort Carson.  Power lines were downed…power poles were toppled…and a number of steel towers carrying high voltage power lines were downed.  Some areas northeast of Denver were without power for a week.  A large number of cattle and sheep were killed by the storm.  The greatest snow depth on the ground at Stapleton International Airport was 12 inches.  Warm temperatures following the storm quickly melted the snow.

In 1995…the third major snow storm of the month dumped heavy snow in and near the Front Range foothills.  Six to 12 inches of heavy wet snow fell in the western metro suburbs with the heaviest amounts above 6 thousand feet.  Both Boulder and Golden measured 10 inches of snow.  Only 2.4 inches of snowfall were measured at the site of the former Stapleton International Airport.  North winds gusted 28 mph at Denver International Airport.

In 1998…the last in a series of April storms blanketed the foothills with heavy snow.  Snowfall amounts included:  17 inches near Blackhawk…15 inches at Idaho Springs…14 inches at Georgetown…11 inches near Conifer and Morrison. Only a trace of snow fell at the site of the former Stapleton International Airport.  North winds gusted to 28 mph at Denver International Airport.

26-27

In 1906…rain changed to heavy snow overnight and totaled 7.0 inches over downtown Denver.  North winds were sustained to 16 mph on both days.  Precipitation totaled 2.16 inches.

In 1932…the temperature remained below freezing for more than 30 consecutive hours.  For about 4 of those hours the temperature hovered around 24 to 25 degrees.  At this time some early cherry trees were in bloom and apple and lilac blossoms were beginning to open.  The leaves of many plants were partly unfurled and vegetation in general was correspondingly advanced due to the warm weather from the 11th to the 22nd.  However…there was little apparent injury to foliage and blossoms…but some of the early cherry and apple blossoms were injured.  Rain changed to snow on the 26th and continued intermittently through the 27th.  Snowfall totaled only 2.0 inches and northeast winds gusted to 22 mph on the 26th.

In 1964…strong winds caused damage to buildings…trees…and power lines.  Sustained winds of 37 mph with gusts of 50 to 60 mph were recorded in metro Denver.  West-northwest winds gusted to 44 mph at Stapleton International Airport on the 26th.

Continue reading April 25 to May 1: This week in Denver weather history →

Photography, Thornton Weather

May 2020 top shots: Monthly photo slideshow

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A beautiful spring sunset. (David Canfield)
A beautiful spring sunset. (David Canfield)

Colorado’s famously highly variable weather seems to showcase itself during the month of May when a variety of weather conditions can be seen.  This provides a prime opportunity for photos of everything weather to flora to fauna.

The month of May can bring extremes.  Snow is not entirely uncommon during the month but more common is severe weather, particularly in the latter half of the month.  Thunderstorms become more frequent and their associated hazards – lightning, wind, hail and tornadoes – are usual visitors.  Providing additional subjects for pictures are the emerging spring flowers and our abundant wildlife.

  • Slideshow updated May 31, 2020. To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

Showcasing images captured by ThorntonWeather.com readers as well as some of our own, our monthly slideshow covers the entire gamut of weather-related imagery.

Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted in images captured from yours and our cameras.

[flickr_set id=”72157714203633883″]

What is missing in the slideshow above?  Your photo!

Our monthly photo slideshow is going to feature images that we have taken but more importantly images that you have captured.  The photos can be of anything even remotely weather-related.

Landscapes, current conditions, wildlife, pets, kids.  Whimsical, newsy, artsy.  Taken at the zoo, some other area attraction, a local park, a national park or your backyard.  You name it, we want to see and share it!

Images can be taken in Thornton, Denver or anywhere across the extraordinary Centennial State.  We’ll even take some from out of state if we can tie it to Colorado somehow.

We’ll keep the criteria very open to interpretation with just about any image eligible to be shown in our slideshows.

What do you win for having your image in our slideshow?  We are just a ‘mom and pop’ outfit and make no money from our site so we really don’t have the means to provide prizes.  However you will have our undying gratitude and the satisfaction that your images are shared on the most popular website in Thornton.

To share you images with us and get them included in the slideshow just email them to us or share them with ThorntonWeather.com on any of the various social media outlets.  Links are provided below.

So come on, get those camera’s rolling!

Climatology, Thornton Weather

May 2019 weather recap: A chilly, unsettled month

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There is little doubt that looking back on the month the most notable feature was the cool, sometimes chilly, temperatures. Denver in fact saw one of its coldest on record. Precipitation for Thornton lagged but Denver itself was quite wet.

A seemingly endless series of storm systems impacted the state through the month. Overall, the first week was seasonal and dry. Temperatures then cooled for a couple of days and delivered us a light shot of snow. We rebounded with a series of 80 degree days from the 13th to the 16 before once again chilling out.

From the 18th to the 23rd, temperatures remained below normal and on the 21st we received a respectable 3.3 inches of snow. Temperatures during that period dropped to below freezing three times.

The balance of the month continued the roller coaster with a few mild days followed by cooler ones.

Thornton’s overall average monthly temperature for May came in at 51.9 degrees. This made it the coldest May since ThorntonWeather.com came online 13 years ago.

Out at DIA where Denver’s official measurements are taken, the month was comparable with a 51.6 degree average. That made May 2019 the seventh coldest May on record and the coldest since 1995.

Highs ranged in Thornton from a maximum of 89 degrees on the 15th down to a lowest reading of 29.8 degrees on the 22nd. Denver’s highest reading of 83 degrees and its coldest of 30 degrees came on the same dates.

Three temperature records were officially set in Denver. The record low for May 21st of 31 degrees was tied. Also on that day, a record low maximum of 39 degrees was set. The old record was 40 degrees set in 1891. Lastly, the low on the 22nd of 30 degrees broke the record low reading for the date of 32 degrees set in 1930.

In terms of precipitation, Denver averages 2.12 inches during the month. Thornton came close to matching that with 2.03 inches. Out at the airport, it was wetter with 3.23 inches being recorded.

Thornton saw a total of 4.1 inches of snow for the month while Denver saw a bit less at 3.9 inches. Both were well above the May average of 1.1 inches.

Click here to view Thornton’s May 2019 climate report.

May 2019 temperature summary for Thornton, Colorado.
May 2019 temperature summary for Thornton, Colorado.
May 2019 precipitation summary for Thornton, Colorado.
May 2019 precipitation summary for Thornton, Colorado.
CLIMATE REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
753 AM MDT SAT JUN 1 2019

...................................

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF MAY 2019...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2019

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              95   05/26/1942
 LOW               19   05/02/2013
                        05/03/1907
HIGHEST            83   05/15
LOWEST             30   05/22
                        05/01

AVG. MAXIMUM     63.9              71.5    -7.6     75.4
AVG. MINIMUM     39.2              42.7    -3.5     47.5
MEAN             51.6              57.1    -5.5     61.4
DAYS MAX >= 90      0               0.8    -0.8        4
DAYS MAX <= 32      0               0.0     0.0        0
DAYS MIN <= 32      7               1.9     5.1        0
DAYS MIN <= 0 0 0.0 0.0 0 PRECIPITATION (INCHES) RECORD MAXIMUM 8.57 1876 MINIMUM 0.06 1974 TOTALS 3.23 2.12 1.11 1.86 DAILY AVG. 0.10 0.07 0.03 0.06 DAYS >= .01        14               9.4     4.6        8
DAYS >= .10         7               4.8     2.2        5
DAYS >= .50         3               1.2     1.8        0
DAYS >= 1.00        1               0.2     0.8        0
GREATEST
 24 HR. TOTAL    1.07   05/20 TO 05/20

SNOWFALL (INCHES)
TOTALS            3.9   2019        1.1 (NCEI 1981-2018 AVG)
RECORD           15.5   1898

DEGREE_DAYS
HEATING TOTAL     414               265     149      151
 SINCE 7/1       6219              5996     223     5401
COOLING TOTAL       5                21     -16       46
 SINCE 1/1          5                22     -17       48

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
.................................................................

WIND (MPH)
AVERAGE WIND SPEED              10.0
RESULTANT WIND SPEED/DIRECTION   1/090
HIGHEST WIND SPEED/DIRECTION    35/310    DATE  05/17
HIGHEST GUST SPEED/DIRECTION    50/310    DATE  05/17

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            3
NUMBER OF DAYS PC             16
NUMBER OF DAYS CLOUDY         12

AVERAGE RH (PERCENT)     64

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.
Photography, Thornton Weather

May 2019 top shots: Monthly photo slideshow

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Beautiful blooms in Thornton start off the month of May. (Lalania Worley)
Beautiful blooms in Thornton start off the month of May. (Lalania Worley)

Colorado’s famously highly variable weather seems to showcase itself during the month of May when a variety of weather conditions can be seen.  This provides a prime opportunity for photos of everything weather to flora to fauna.

The month of May can bring extremes.  Snow is not entirely uncommon during the month but more common is severe weather, particularly in the latter half of the month.  Thunderstorms become more frequent and their associated hazards – lightning, wind, hail and tornadoes – are usual visitors.  Providing additional subjects for pictures are the emerging spring flowers and our abundant wildlife.

  • Slideshow updated May 27, 2019. To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

Showcasing images captured by ThorntonWeather.com readers as well as some of our own, our monthly slideshow covers the entire gamut of weather-related imagery.

Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted in images captured from yours and our cameras.

What is missing in the slideshow above?  Your photo!

Our monthly photo slideshow is going to feature images that we have taken but more importantly images that you have captured.  The photos can be of anything even remotely weather-related.

Landscapes, current conditions, wildlife, pets, kids.  Whimsical, newsy, artsy.  Taken at the zoo, some other area attraction, a local park, a national park or your backyard.  You name it, we want to see and share it!

Images can be taken in Thornton, Denver or anywhere across the extraordinary Centennial State.  We’ll even take some from out of state if we can tie it to Colorado somehow.

We’ll keep the criteria very open to interpretation with just about any image eligible to be shown in our slideshows.

What do you win for having your image in our slideshow?  We are just a ‘mom and pop’ outfit and make no money from our site so we really don’t have the means to provide prizes.  However you will have our undying gratitude and the satisfaction that your images are shared on the most popular website in Thornton.

To share you images with us and get them included in the slideshow just email them to us or share them with ThorntonWeather.com on any of the various social media outlets.  Links are provided below.

So come on, get those camera’s rolling!

Thornton Weather

Thornton’s May weather preview: Snow begins to give way to severe storms

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Thornton, Colorado May 2013 weather preview.
Thornton, Colorado May 2013 weather preview.

Colorado’s famously highly variable weather seems to showcase itself during the month of May when a variety of weather conditions can be seen.

Winter-like temperatures and snow are possible as are mid-summer like temperatures or the more typical spring severe weather.

As the month starts out in 2019 we are going to wear off the chill of recent days and warm up nicely but cooler and wetter weather appear to be on the way.  Long range forecasts predict we may be seeing cooler than normal temperatures with above normal precipitation for the month.

The month can certainly bring extremes.  Snow is not entirely uncommon during the month, oftentimes causing damage to newly bloomed trees.  More common however is severe weather, particularly in the latter half of the month.  Thunderstorms become more frequent and their associated hazards – lightning, wind, hail and tornadoes – are usual visitors.

For a complete look at what lies ahead for the month of May, check out our full preview here.

Thornton Weather

May 2018 weather recap: Warmer and drier than normal

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The month of May started off cool and damp but that did not last long.  It soon dried out and warmed up leading to one of the warmest Mays on record.

The first three days of the month brought cool temperatures and generous amounts of rain, more than one inch total.  We then followed that up with a warming trend that for a week.

Temperatures then cooled for the 12th and 13th of the month then started their upward trend again. Another, short break from the warmth came along from the 18th to the 20th.

After that, the warm weather returned and the last eleven days of the month all saw above normal mercury readings.

While there were a few days with rain after the wet start, none really amounted to much.

Thornton’s average temperature for the month came in at 60.5 degrees. By comparison, Denver’s long term average temperature for May is 57.1 degrees. Out at the airport where Denver’s official readings are taken, the month’s average temperature was warmer than ours at 61.4 degrees. That made the month the eight warmest May in Denver history.

Thornton saw its warmest temperature reading for the month of 92.4 degrees on the 26th of the month. The lowest reading of 35.4 degrees fell on the 4th.  Denver saw its warmest reading of 94 degrees on the same day we saw our warmest and its coldest of 40 degrees on the 20th.

Denver set a record high temperature on the 10th and tied the record high temperature for the 25th.  Additionally, the Mile High City saw four days with high temperatures at or above the 90 degree mark (Thornton had three). This breaks the record for the number of 90 degree days in May which previously was three days set in 1989 and 1874.

In terms of precipitation, Denver averages 2.12 inches during May.  Thornton fell well short with 1.59 inches in our bucket. The Mile High City fared better, but still below normal, with 1.86 inches.

No snow fell during the month in Thornton or Denver.

Click here to view Thornton’s May 2018 climate report.

Thornton, Colorado's May 2018 temperature summary. (ThorntonWeather.com)
Thornton, Colorado’s May 2018 temperature summary. (ThorntonWeather.com)
Thornton, Colorado's May 2018 precipitation summary. (ThorntonWeather.com)
Thornton, Colorado’s May 2018 precipitation summary. (ThorntonWeather.com)
CLIMATE REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
942 AM MDT FRI JUN 1 2018

...................................

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF MAY 2018...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2018

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              95   05/26/1942
 LOW               19   05/02/2013
                        05/03/1907
HIGHEST            94   05/26                         86  05/06
LOWEST             40   05/20                         32  05/04
                        05/03
                        05/02
AVG. MAXIMUM     75.4              71.5     3.9     69.6
AVG. MINIMUM     47.5              42.7     4.8     42.3
MEAN             61.4              57.1     4.3     55.9
DAYS MAX >= 90      4               0.8     3.2        0
DAYS MAX <= 32      0               0.0     0.0        0
DAYS MIN <= 32      0               1.9    -1.9        1
DAYS MIN <= 0       0               0.0     0.0        0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         8.57   1876
 MINIMUM         0.06   1974
TOTALS           1.86              2.12   -0.26     3.66
DAILY AVG.       0.06              0.07   -0.01     0.12
DAYS >= .01         8               9.4    -1.4       17
DAYS >= .10         5               4.8     0.2       11
DAYS >= .50         0               1.2    -1.2        2
DAYS >= 1.00        0               0.2    -0.2        1
GREATEST
 24 HR. TOTAL    0.49   05/03 TO 05/03           05/18 TO 05/18

SNOWFALL (INCHES)
TOTALS            0.0               1.1

DEGREE_DAYS
HEATING TOTAL     151               265    -114      281
 SINCE 7/1       5401              5996    -595     5084
COOLING TOTAL      46                21      25        6
 SINCE 1/1         48                22      26        6

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
.................................................................

WIND (MPH)
AVERAGE WIND SPEED              9.9
RESULTANT WIND SPEED/DIRECTION   1/116
HIGHEST WIND SPEED/DIRECTION    36/330    DATE  05/30
HIGHEST GUST SPEED/DIRECTION    52/330    DATE  05/30

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            6
NUMBER OF DAYS PC             15
NUMBER OF DAYS CLOUDY         10

AVERAGE RH (PERCENT)     57

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORMS            11   MIXED PRECIP           3
HEAVY RAIN                2   RAIN                   2
LIGHT RAIN               11   FREEZING RAIN          0
LT FREEZING RAIN          0   HAIL                   3
HEAVY SNOW                0   SNOW                   0
LIGHT SNOW                0   FOG W/VIS <=1/4 MILE   6
FOG                      10   HAZE                   3

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.
Weather History

May 27 to June 2: This Week in Denver Weather History

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This week in Denver weather history
May 27 to June 2: This Week in Denver Weather History

A very eventful week in Denver weather history with everything from thunderstorms and tornadoes to yes, even snow.

From the National Weather Service:

20-27

In 2002…lightning sparked a wildfire near Deckers. Extremely dry conditions and very strong winds the following day allowed the fire…known as the Schoonover…to consume 3850 acres before it could be contained. Thirteen structures were destroyed…including 4 homes…resulting in 2.2 million dollars in damage.

26-31

In 1995…a cool period with light morning showers and moderate to heavy afternoon showers and thunderstorms pushed rivers already swollen from mountain snow melt over their banks causing minor flooding. Streams and rivers such as the South Platte and Boulder Creek flooded meadowlands…bike paths…roads near streams…and other low lying areas. No significant property damage was reported and crop damage was unknown. Rainfall totaled 1.79 inches at the site of the former Stapleton International Airport and only 1.51 inches at Denver International Airport.

27

In 1874…an apparent thunderstorm gust front reached the city at 6:40 pm. Strong southwest winds sustained to 48 mph for a few minutes produced large columns of dust in the city and on the prairie. There was no rain in the city.

In 1942…a duststorm swept into the city…but no damage was reported. West winds were sustained to 23 mph.

In 1953…a heavy hailstorm caused an estimated 100 thousand dollars damage across metro Denver. Larger than golf ball size hail fell in Westminster and north Denver. Only 1/8 inch hail was measured at Stapleton Airport.

In 1955…west-northwest winds at 35 mph with gusts as high as 58 mph briefly reduced the visibility to 1/2 mile in blowing dust at Stapleton Airport.

In 1981…lightning damaged power lines west of Lakewood and blew up a transformer at the Denver Federal Center. Hail 1 to 1 1/2 inches in diameter was reported in Lakewood and on I-25 south of Denver.

In 2001…hail as large as 3/4 inch in diameter was measured near Commerce City.

In 2003…hail to 3/4 inch in diameter fell near Central City.

In 2006…unusually warm weather for late May produced two temperature records. The high temperature of 93 degrees was a record maximum for the date. The low temperature of 59 degrees equaled the record high minimum temperature for the date. Both previous records occurred in 1895.

28

In 1884…a thunderstorm apparently produced large hail. The hail stones were noted as unusually large…but the diameter of the stones was not measured. The hail fell for only 5 minutes. Precipitation from the storm was only 0.05 inch.

In 1898…heavy thunderstorm rainfall totaled 1.74 inches in downtown Denver. Hail of unknown size accompanied the storm.

In 1981…a woman in Aurora was struck and killed by lightning. Another bolt injured a boy on a bicycle at about the same time a short distance away. About half an inch of rain in 20 minutes caused street flooding in the area. A tornado touched down for about 2 minutes some 3 miles north of Stapleton International Airport.

In 1982…severe thunderstorms produced golf ball size hail in southeast Denver…Aurora…and Strasburg. The large hailstones undoubtedly damaged some cars in the area. At Stapleton International Airport…only 1/2 inch diameter hail was measured.

In 1991…golf ball size hail fell in Brighton. No damage was reported. Later…hail ranging in size from 3/4 inch to 1 1/2 inches in diameter fell over southwestern sections of metro Denver. In some areas…hail piled up a few inches in depth.

In 1994…thunderstorm wind gusts to 65 mph damaged 16 small airplanes and a hangar at centennial airport.

In 2001…severe thunderstorms produced large hail across metro Denver. Hail as large as 1 inch in diameter fell in Lakewood…Wheat Ridge…northwest Denver…near Watkins… Bennett…and Keenesburg. Hail 3/4 inch or larger fell in Brighton. Thunderstorm winds gusted to 58 mph at Denver International Airport. A small tornado (f0) touched down near Bennett…but did no damage.

29

In 1934…the low temperature dipped to only 66 degrees…the all-time record highest minimum temperature for the month of May.

In 1958…a microburst caused a brief wind gust to 56 mph at Stapleton Airport.

In 1964…heavy rain caused flooding in the Harvey Gulch area of southeast Denver. The high water damaged homes… Businesses…streets…and bridges. At Stapleton International Airport…1.33 inches of rain were measured with 1.76 inches total rainfall on the 29th and 30th. The heavy rain during the last week of the month was the first significant precipitation since April 3rd.

In 1967…3/4 to 1 inch diameter hail stones fell in the city of Denver…but caused no reported damage. Hail as large as 3/4 inch was measured at Stapleton International Airport.

In 1975…the heaviest last snowfall of the season occurred when 5.6 inches of snow were measured at Stapleton International Airport. Rain all day on the 28th changed to snow on the 29th and accumulated to a depth of 4 inches on the ground. Northwest winds gusted to 31 mph. Precipitation (rain and melted snow) on the 28th and 29th totaled 1.48 inches.

In 1982…one man was killed and two others injured by a lightning strike as they stood under a tree in the city of Denver’s Washington Park.

In 1987…7/8 inch diameter hail fell near Castle Rock.

In 1990…thunderstorms over metro Denver produced several small funnel clouds and two small tornadoes. The first tornado (f0) touched down in northwest Denver and caused roof damage to a house and snapped off the tops of several trees. A second tornado (f1) touched down in Northglenn and moved into Thornton damaging a group of self storage garages…several vehicles…a wooden fence…several trees… And the roof of an auto parts store. No injuries were reported. The storms also caused minor street flooding across northern and western sections of metro Denver. Rainfall totals ranged from 1 to 3 inches. Lightning started a small fire at a home in northwest Denver. The fire was confined to the front rooms and was quickly extinguished. Snow plows were used to clear 2 to 4 inches of pea to marble size hail from a stretch of U.S. Highway 285 in turkey creek canyon. Lightning felled a tree in northeast Denver…while strong winds snapped off several large tree limbs in the same area. Thunderstorm rainfall totaled 0.82 inch at Stapleton International Airport where southwest winds gusted to 30 mph.

In 1991…lightning struck a 13 year old boy in a field in Fort Lupton. The boy was in critical condition in an area hospital for 2 days before recovering.

In 1995…lightning struck a soccer goal post and injured 6 adults viewing a soccer game in Arvada. Although no one received a direct hit from the lightning…all escaped with only minor injuries…except one woman who was hospitalized.

In 1996…large hail…3/4 to 1 1/2 inches in diameter… Struck Lakewood and west Denver. Lightning sparked a small fire when it struck an oil storage tank 5 miles west of Brighton.

In 2001…lightning sparked a fire in an apartment complex in Aurora…forcing the evacuation of 24 units. Most of the fire damage was confined to the attic. Damage was estimated at 100 thousand dollars.

In 2004…a man and his son were struck by lightning while practicing on the driving range at the meadows golf club in southwest metro Denver. The father was killed by the bolt…and his 16 year old son seriously injured. Three other people standing nearby received only minor injuries.

In 2010…hail up to 7/8 inch in diameter was reported in Broomfield.

In 2017…an isolated thunderstorm produced hail up to 7/8 inch in diameter near Centennial.

Continue reading May 27 to June 2: This Week in Denver Weather History →