Thornton, Colorado, USA
UpdatedWed, 25-Nov-2020 12:15pm MST 


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Denver sees first 90 degree day of the year, sets record high temp for May 19

Tuesday, May 19th, 2020 4:31pm MST

Record High Temperature

We knew getting our first 90 degree reading of the year was a possibility today and sure enough, we did. Not only that, Denver also set a record high temperature for the date.

As measured at Denver International Airport, the high temperature in the Mile High City hit 92 degrees today. That tops the old record high temperature for May 19 of 90 degrees set in 2009.

Thornton held itself just a bit cooler with a high of 91 degrees.

On average, Denver sees its first 90 degree day on June 10 so we are a few weeks ahead of schedule.

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Toasty temperatures for Tuesday, just a slight chance for thunderstorms

Tuesday, May 19th, 2020 5:09am MST

Today’s weather in #Thornton looks to be much like yesterday with the unseasonably warm temperatures and a good bit of sun. We do, however, mix in some scattered thunderstorm activity.

Sunny skies start us off and then we will see a few clouds later this morning and afternoon. High temperatures will again reach the upper 80s. Breezy winds will arrive this afternoon and last until about midnight.

Scattered thunderstorms are expected to develop after 2:00pm and into the evening. Most activity should be to our north and northeast but we will want to keep an eye out for something close to home.

Tonight, partly clear skies will be above with overnight lows in the mid-50s.

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Thornton’s 2019 / 2020 snow season comes in as second snowiest of past 13 years

Monday, May 18th, 2020 7:31am MST
Thornton, Colorado's 2019 / 2020 snow season report and totals. Click for larger view. (ThorntonWeather.com)

Thornton, Colorado’s 2019 / 2020 snow season report and totals. Click for larger view. (ThorntonWeather.com)

As it appears we are done with the white stuff for the season, we can now report a finally tally for snow.

Thornton’s season recorded 84.3 inches, the second most since Thornton Weather came online in 2006. Only the 2015 / 2016 season had more (85.7 inches).

The total is most notable because we never did receive a truly big storm, just a number of respectable ones. The totals were helped by big months in October, November and February which overcame a very dry December and January.

Officially, as measured at Denver International Airport, only 57.6 inches was recorded. This was a mere 1/2 inch more than Denver’s long term seasonal average of 57.1 inches.

Those numbers continue to reflect the problem with having the Mile High City’s official weather station located out at the airport where it is in a totally different microclimate whose conditions don’t reflect what the metro area really sees.

For comparison, the site at Stapleton closest to where Denver’s records were recorded for 57 years before the move to DIA saw 71.4 inches of snow this season.

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Unseasonably warm temperatures, dry conditions start off Thornton’s workweek

Monday, May 18th, 2020 5:03am MST

The warming trend that started this weekend continues right into today. We will be seeing temperatures about 15 degrees above normal while remaining dry.

Mostly sunny skies start us off and will be with us for much of the day. High temperatures today will reach the mid to upper 80s. This is well above Denver’s long term average high for the date of 72 degrees. Winds will be a bit breezy this evening.

Tonight, skies will be mostly clear with lows in the mid-50s.

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Thornton’s weekend starts out stormy, will end calmer and warmer

Friday, May 15th, 2020 4:54am MST

A pretty typical springtime weather pattern on tap for the three day period. Friday will feature temps near normal but with a good chance for storms but then the rest of the weekend will be warmer and calmer.

Today brings mostly cloudy conditions as a good bit of moisture has settled in. Highs today will be right near the average high of 70 degrees for the date. PM thunderstorms are expected to develop, mainly in the mid-afternoon to early evening. The worst of these should be east of us but some will have the potential for strong winds and hail. Tonight, storm activity will end by midnight and overnight lows will dip to the mid-40s.

Saturday should offer a good dose of sun with mostly sunny skies and highs in the low 70s. There will be just a slight chance for thunderstorms in the afternoon and evening. Saturday night into Sunday morning, partly cloudy skies will be above with lows in the upper 40s.

Sunday looks to be the warmest day of the period with highs near the 80 degree mark under mostly sunny skies. There is just a slight chance for a PM thunderstorm. Have a great weekend!

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Thornton’s Thursday cools down to near normal temps, brings decent chance for storms

Thursday, May 14th, 2020 5:30am MST

With the passing of a cold front, our weather cools down and afternoon and evening thunderstorms will threaten.

Mostly sunny skies will be with us until late morning / early afternoon. Clouds will then increase leading to partly clear conditions. High temperatures today will top out right near the average high for the date of 71 degrees.

Scattered thunderstorms will develop after noon and increase in coverage in the mid-afternoon to early evening hours. Gusty winds, perhaps some small hail will be the biggest threats.

Tonight, storm activity will end by midnight. Overnight lows will be in the mid-40s.

Keep an eye out for the storms with our interactive radar here.

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A warm Wednesday as Thornton will enjoy temps well above normal

Wednesday, May 13th, 2020 5:06am MST

Weather conditions look to warm up a good ways today as highs will come in about 10 degrees above average for the date.

Mostly sunny skies will be the general rule most of the day with a bit of an increase in clouds in the late afternoon. High temperatures today will top out right near the 80 degree mark. Conditions will be dry and overall calm.

Tonight, a weak cold front will be moving through leading to increased clouds. Overnight lows will drop to the mid to upper 40s.

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May 10 to May 16: This week in Denver weather history

Wednesday, May 13th, 2020 4:40am MST

This Week in Denver Weather History

As we move further into spring we begin to less winter-like weather and more spring weather.  In looking at Denver weather history we can see that transition with more mentions of severe rains, flooding, tornadoes and other spring and summer-like severe weather.

From the National Weather Service:


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.


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.


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.


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.


In 2011…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.


In 1879…an apparent cold front during the afternoon produced sustained north winds as high as 60 mph and great clouds of blowing dust.  The dust filled the air until the thunderstorm rain began…which produced 1.46 inches of rainfall.  The rain ended during the evening.

In 1900…southwest winds were sustained to 40 mph with gusts to 46 mph.

In 1958…a microburst caused a brief wind gust to 55 mph at Stapleton Airport.

In 1963…south-southwest winds gusted to 48 mph at Stapleton Airport.  Winds May have been stronger over west Denver where some buildings were damaged.

In 1998…large hail fell over south metro Denver.  Hail as large as 1 1/4 inches in diameter was measured in Parker with 1 inch hail recorded in Littleton and 4 miles south of Lakewood in Jefferson County.  Hail to 3/4 inch diameter was measured in Douglas County…11 miles west- northwest of Parker.


In 2014…a strong storm system moved from southwest Colorado and produced heavy snow in and near the Front Range foothills and metro Denver. The snow was heaviest in the foothills where up to 2 1/2 feet of snow was observed. In the foothills… Storm totals included: 30 inches near Pinecliffe; 29 inches… 8 miles northeast of Four Corners; 28 inches near Pingree Park; 27 inches near Allenspark; 20.5 inches near Idaho Springs; 19.5 inches at Gold Hill; 19 inches near Genesee; 18 inches near Blackhawk; 17 inches at Aspen Springs; 16.5 inches near Ward; 13.5 inches at bergen park; with 11 inches at Evergreen. Along the urban corridor and Palmer Divide…storm totals included: 10.5 inches at Eldorado Springs; 10 inches at Ken Caryl; 9 inches at Superior; 8 inches near Morrison; 7.5 inches in Broomfield and Highlands Ranch; 7 inches in Denver… Near Franktown…Golden… Lakewood and Highlands Ranch; 6 inches…5 miles northeast of Westminster… 7 miles south of Lyons and near Parker; with 5.5 inches at Aurora. At Denver International Airport…1.1 inches of snowfall was observed… Along with 0.9 inches of water.


In 1875…two forest fires on the eastern slope of the foothills were visible from the city.

In 1904…north winds were sustained to 40 mph with gusts to 48 mph.

In 1950…brilliant and complete primary and secondary rainbows arching across the sky were observed from Stapleton Airport.

In 1951…a wind gust to 51 mph was recorded at Stapleton Airport.

In 1984…winds gusted to 69 mph in Boulder.  Northwest winds gusted to 47 mph at Stapleton International Airport.

In 1987…a small weak tornado touched down for about 2 minutes in southeast Denver.  The twister hit a car dealership…blowing about a dozen windows out of cars and shattering four skylights on the building.  Some tin roofing was blown off a patio a block and a half away.  The tornado also downed a power pole.  Damage at the dealership was estimated at 10 thousand dollars.  A man was slightly injured by lightning in northwest Aurora.

In 1995…several funnel clouds were sighted near Parker. One of the funnels produced a short-lived debris cloud on the ground in an open field.  No damage was reported.

In 2015…a man suffered minor injuries when the tree he took shelter under was struck by lightning. He was jogging at City Park Golf Course when the incident occurred. The jogger was taken to the hospital for observation.


In 1907…the temperature warmed to a high of 73 degrees on the 12th…before a cold front produced a thunderstorm… Northeast winds sustained to 40 mph…and rain changing to light snow overnight.  Snowfall totaled only 2 inches…but the high temperature on the 13th was only 39 degrees.

In 1961…a storm that covered metro Denver with rain and snow started as thunderstorms on the evening of the 12th.  Hail to 1 1/2 inches in diameter was reported 10 miles northwest of Stapleton Airport.  Rain continued overnight and changed to snow on the 13th.  Snowfall totaled 6.4 inches and precipitation (rain and melted snow) 1.96 inches at Stapleton Airport where north winds gusted to 39 mph.  The rain and heavy wet snow caused icing damage to utility lines.  Heavy snow occurred in the foothills.

In 1982…a major storm dumped 1.50 to 3.50 inches of rain across northeast Colorado and deposited prodigious amounts of snow in the foothills.  Coal Creek Canyon southwest of Boulder was buried under 46 inches of snow with 39 inches at Nederland.  The heavy wet snow downed many powerlines in the foothills.  In Thornton…the roof of a school was damaged by water from the heavy rain.  At Stapleton International Airport…1.49 inches of rain were measured over the two day period.  The heavy rain ended a severe and prolonged drought.

In 2004…a winter storm produced heavy snow in excess of a foot in the foothills above 6 thousand feet while heavy rain fell across the city.  The heaviest snow occurred in the high country of Boulder County.  Storm total snowfall was 14.5 inches near Jamestown.  Rainfall totaled 0.81 inch at Denver International Airport with 0.94 inch recorded at Denver Stapleton.  A trace of snow was recorded at both locations.  East winds gusted to 24 mph at Denver International Airport on the 12th.


In 1905…a thunderstorm produced hail during the late afternoon.  Precipitation totaled 0.57 inch.


In 1912…heavy snowfall totaled 12.4 inches over the city. Most of the snow…9.9 inches…fell on the 13th…which was the greatest 24 hour snowfall in May at the time.  This was the last snowfall of the season.  The low temperature dipped to 27 degrees on the morning of the 14th.

In 1989…a spring storm brought heavy rain and snow to the foothills.  Metro Denver was soaked with 1 to 2 inches of rain.  Rainfall totaled 1.26 inches at Stapleton International Airport.  In the foothills…Echo Lake received 20 inches of snow.  A 30-ton Boulder slid onto I-70 east of the Eisenhower Tunnel…closing the freeway for 2 hours.


In 1910…a thunderstorm produced strong winds during the afternoon.  Northwest winds were sustained to 42 mph.

In 1913…light moist snow and light hail fell during short intervals…although no thunder was heard.  The trace of snowfall was the only snow of the month.  Precipitation… Mostly rain…totaled 0.44 inch.

In 1984…a pilot reported a tornado 16 miles east of Stapleton International Airport.  No damage was reported. A thunderstorm produced a 58 mph wind gust in Brighton. Thunderstorm winds gusted to 48 mph at Stapleton International Airport.

In 1989…lightning struck a home in evergreen…setting it afire.

In 1992…strong thunderstorm winds of unknown velocity… Knocked over and damaged the infield tote board at Arapahoe Park Racetrack just southeast of Aurora. Damage was estimated at 200 thousand dollars.  No injuries were reported.  Lightning started two house fires…causing 35 hundred dollars in damage in Adams County just 9 miles north-northwest of Denver.

In 1994…a sudden wind gust…estimated at 40 mph…blew a portion of the roof off a shopping center in Lafayette. The roof also damaged two parked cars in an adjacent lot.

In 2001…a construction worker in Castle Rock received minor injuries when lightning struck close-by.

In 2002…a microburst wind gust to 53 mph was recorded at Denver International Airport.

In 2007…severe thunderstorms producing large hail…very heavy rain…and tornadoes impacted the urban corridor and adjacent plains.  Heavy rain associated with a severe thunderstorm caused flooding along a small tributary draining into the South Platte River.  The incident took place at 13th and Decatur St….near Invesco Field.  The floodwaters inundated the bike trail adjacent to the creek. A woman with her child sought refuge under a bridge and became trapped by the high water.  The woman slipped and the stroller containing the child was swept into the swift current.  The child drowned.  Rainfall totaled 0.42 inches at Denver International Airport.  Elsewhere…golfball hail was reported near Hudson.  Hail…up to one inch in diameter…was observed in Boulder and Lyons. Thunderstorm wind gusts estimated to 70 mph were reported near Buckley Air Force Base…with a peak wind gust to 37 mph observed at Denver International Airport.  A small tornado touched down near Ft. Lupton but did no damage.


In 1977…high winds up to 100 mph felled hundreds of trees in Gilpin County and caused extensive damage to telephone and power lines.  Lumber and steel tanks were blown around in Boulder canyon.  West winds gusted to 46 mph at Stapleton International Airport on the 15th.


In 1996…a period of unusually warm weather resulted in 4 record maximum temperatures in 5 days.  The record high temperatures were 87 degrees on the 14th…89 degrees on the 15th…and 93 degrees on both the 16th and 18th.  The temperature climbed to only 81 degrees on the 17th which was not a record.

» Click here to read the rest of May 10 to May 16: This week in Denver weather history

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Tuesday to offer dry conditions, seasonal temperatures

Tuesday, May 12th, 2020 5:13am MST

A pretty nice looking day ahead for Thornton. We do have some clouds and fog to start things off but those will give way to mostly sunny skies later and high temperatures will be near normal.

Low clouds are above early and we are seeing some patchy fog. By about 9:00am the fog will dissipate and the clouds ease and the late morning / early afternoon will bring mostly sunny skies. High temperatures today will reach the upper 60s.

Tonight, skies will be partly cloudy with overnight lows in the mid-40s.

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Cool, unsettled weather conditions start off Thornton’s workweek

Monday, May 11th, 2020 5:02am MST

A passing disturbance will mix things up with our weather today. Temperatures will be a good bit cooler than normal and some light rain, perhaps a thunderstorm will be seen.

Mostly cloudy skies start of the morning and will be with us through the day. High temperatures today will only reach around 60 degrees. Some drizzle will be possible by late morning with the afternoon bringing a better chance for activity. A bit of thunder may get thrown into the mix as well. Tonight, skies remain mostly cloudy and some patchy fog may be seen.

Overnight lows will dip to the low 40s. Keep an eye out for those showers with our interactive radar here.

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