Thornton, Colorado, USA
UpdatedSat, 25-Sep-2021 5:35am MDT 


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After a warm start, most of Thornton’s Memorial Day weekend to be cooler, wetter

Friday, May 28th, 2021 5:06am MDT

Unfortunately, not exactly ideal weather conditions for the holiday weekend. Friday will be the warmest and nicest day of the period but then conditions become unsettled and wet for the latter half.

For today, after some early, low clouds / fog, mostly sunny skies will be above for the balance. Highs will top out near the 80 degree mark. There is just a slight chance to see a thunderstorm in the mid to late afternoon. Tonight, skies will be partly clear with overnight lows near 50 degrees.

A front moves in Saturday and that will start a trend toward cooler, unsettled conditions. It will be mostly sunny early then clouds will slowly increase. Highs will top out around the 70 degree mark. The afternoon and evening will bring some scattered thunderstorm activity. Saturday night, showers will be possible with lows around 50 degrees.

Sunday is going to be the least desirable day of the period. Mostly cloudy to cloudy skies will be above with some breezy winds. Rain showers will be pretty dominant, particularly in the afternoon. Highs will only be around 60. Sunday night into Monday showers will ease some with lows in the mid-40s.

Memorial Day will see some improvement over Sunday but not much. Mostly cloudy skies will remain and showers will decrease a bit but still be possible, particularly in the afternoon. Highs will be in the low 60s.

Have a great weekend and please, take time to remember the fallen – they are the reason for Memorial Day.

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Thursday to offer up temps near normal, dry conditions

Thursday, May 27th, 2021 5:07am MDT

A pretty good looking day ahead for us with relatively calm conditions and comfortable temps. Looking ahead to the holiday weekend, conditions won’t be as warm or as dry.

For today, we will have a bit of cloud cover early on then that will ease leading to mostly sunny skies for most of the day. We will remain dry today but with some breezy east winds, mainly this afternoon. High temperatures will top out in the mid-70s.

Tonight, skies will remain mostly clear with lows in the mid-40s.

Looking ahead, after a warmer than normal day tomorrow, the balance of the weekend looks cooler and less stable. Showers will arrive Saturday PM and then Sunday and Monday will see much cooler temps and rain. Check out the extended forecast for more details.

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Mild temperatures, a good bit of cloud cover, just a bit of a chance for storms Wednesday

Wednesday, May 26th, 2021 5:06am MDT

With a trough approaching, moisture aloft is increasing and that will lead to clouds today. Those will, however, not do much to inhibit temperatures and we will have a mild day.

Partly sunny skies start us of and clouds will soon increase bringing mostly cloudy conditions for most of the day. High temperatures will top out in the mid to upper 70s again. Conditions will be calm for much of the day. We do see just a slight chance for a thunderstorm to pop up from about 3:00pm to 6:00pm.

Tonight, skies will be clearing with lows around 50 degrees.

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Mild, calm conditions for Thornton’s Tuesday

Tuesday, May 25th, 2021 4:59am MDT

Another good-looking day ahead for us. Temperatures will be a bit warmer than yesterday and we continue to see a lot of that Colorado blue above.

Clear skies start us off and will be with us for the morning. A few clouds will pop up this afternoon but won’t be too intrusive. High temperatures today will top out in the mid to upper 70s. Overall conditions will be calm and dry.

Tonight, cloud cover will increase and overnight lows will drop to around 50 degrees.

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May 23 to May 29: This week in Denver weather history

Tuesday, May 25th, 2021 4:58am MDT

This Week in Denver Weather History

We are getting closer to Colorado’s severe weather season and see how dangerous it can be when we look back in Denver weather history.  Many occurrences of dangerous lightning, large hail, flooding and tornadoes have been the hallmark of this week in Denver weather history.


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.


In 1876…snow changed to heavy rain over the city…resulting in widespread flooding along Cherry Creek and the South Platte River…nearly as great as the flash flood of May 19-20…1864.  However…damage was greater because the city had grown much larger and there were more bridges for the flood waters to destroy.  Precipitation in the city totaled 6.70 inches from 10:00 pm on the 21st through 3:00 am on the 23rd.  The greatest precipitation ever recorded in Denver in 24 hours…6.53 inches…occurred on the 21st and 22nd.  Small buildings and bridges along Cherry Creek were washed away by the flood waters.  Bridges over the South Platte River were damaged.  The city irrigation ditch was damaged and rendered unfit for service.  Strong winds at speeds of 30 to 40 mph drove the heavy rain through brick walls 12 to 16 inches thick.  Many sheep and cattle were either killed by lightning or drowned…including some 100 head of cattle in Jefferson County alone.  There was immense damage to railroad tracks…especially the Kansas Pacific line to the east of the city.  The Colorado Central suffered estimated damage of 10 to 15 thousand dollars.  In addition…the heavy rain caused extensive flooding on soda and bear creeks in the foothills.  Flooding along Boulder creek inundated farm and pasture land in the Boulder valley and damaged a few bridges.  Rail travel had to be suspended in the area for several days.


In 1933…high winds and gales overnight caused considerable damage in and near the city.  Much greenhouse glass was broken…which caused damage to sheltered plants.  Great numbers of plants growing in the open were damaged or killed by wind-driven sand and soil.  Fields were eroded by the wind and a few trees were uprooted.  West winds were sustained to 38 mph with gusts as high as 65 mph in downtown Denver on the 22nd.


In 1916…southeast winds were sustained to 43 mph with gusts as high as 52 mph.  The winds were strong for several hours during the afternoon.

In 1965…thunderstorm outflow wind gusts to 59 mph were recorded at Stapleton International Airport.

In 1987…slow moving thunderstorms bombarded metro Denver. One inch diameter hail was reported in south central Denver.  Torrential rain caused widespread street flooding… Stalling traffic throughout the area.  Rainfall totaled 2.10 inches in just 25 minutes in extreme southeast Aurora. Many other locations in Aurora and east Denver reported 1 to 1 1/2 inches of rain in about 30 minutes.  Thunderstorm rainfall totaled 1.33 inches at Stapleton International Airport where 1/4 inch diameter hail was measured and north winds gusted to 40 mph.  A man was slightly injured by lightning near Stapleton International Airport.  Lightning also started a fire that severely damaged a house in Aurora.

In 1990…a microburst wind gust to 52 mph at Stapleton International Airport produced some blowing dust.

In 1991…thunderstorms moving from southwestern sections of metro Denver to the east of Denver produced large hail up to golf ball size.  An estimated 5 thousand homes and 8 thousand cars received considerable damage.  Early estimates placed damage costs around 60 million dollars. Three funnel clouds were also reported…two by personnel at Buckley Field and the other by a storm spotter.  Heavy rain produced street flooding in Aurora where hail accumulated to a depth of 6 inches.  As the storms moved to the east…golf ball size hail was reported at Strasburg.

In 1997…hail to 3/4 inch diameter fell in Broomfield.

In 2002…a very strong microburst near Strasburg swept a woman into a swirl of dirt and carried her about 150 feet. The woman was in an open field…corralling a yearling horse… When the incident occurred.  Fortunately…she received only minor injuries.


In 2002…a pacific storm system brought much needed snow to the mountains and foothills with a mix of rain and snow on the plains.  The most snow fell from central Jefferson County northward.  Snow totals included:  13 inches in Coal Creek Canyon…11 inches near Evergreen and atop gold hill… 10 inches near Blackhawk and conifer and atop Crow Hill… 9 inches near Rollinsville…and 8 inches near Genesee and Golden.  Rain was mixed with snow across the city. Precipitation totaled 0.61 inch at Denver International Airport.  Snowfall was less than an inch at the site of the former Stapleton International Airport.  The storm brought unseasonably cold air to metro Denver.  Three temperature records were set.  Low temperature of 31 degrees on the 23rd was a record minimum for the date…as was the low of 32 degrees on the 24th.  The high temperature of only 48 degrees equaled the record low maximum for the date.


In 1953…a microburst caused a brief wind gust to 55 mph at Stapleton Airport.

In 1957…walnut size hail…1 1/2 inches in diameter…fell in east Denver.  Only 1/4 inch hail was measured at Stapleton Airport.

In 1958…rainfall totaled 1 to 2 inches across metro Denver. Rainfall was only 0.37 inches at Stapleton Airport.

In 1974…a tornado was observed briefly near Watkins.  No damage was reported.

In 1980…strong gusty winds of at least 60 mph damaged buildings in parts of Denver.  Several buildings were unroofed in Sheridan.  The flying debris damaged other structures.  Strong microburst winds gusted to 52 mph at Stapleton International Airport.

In 1991…a tornado touched down briefly in open country near Bennett.  No damage was reported.

In 1994…weather spotters reported 2 funnel clouds over Aurora and a short-lived waterspout on Cheery Creek Reservoir.

In 1997…hail to 1 inch in diameter fell in Broomfield with 3/4 inch hail measured in Boulder.

In 1998…a tornado struck a wooden hangar at the Aurora airpark.  The hangar collapsed…damaging a car and a single engine plane parked inside.  An adjacent steel hangar sustained only minor damage.  The tornado moved northeast…hopped I-70…and touched down again in an open field.  Earlier…a weak tornado touched down briefly in an open field 10 miles southeast of Buckley Field.

In 2003…severe thunderstorms produced large hail over northern and southern metro Denver.  Hail as large as 2 3/4 inches in diameter was measured 10 miles northwest of Hudson and to 2 inches in diameter 10 miles northeast of Fort Lupton.  One inch diameter hail fell in Fort Lupton.  Hail to 1 inch in diameter fell near Parker and to 3/4 inch near Franktown.

In 2004…severe thunderstorms moved across northwest and north metro Denver.  Hail as large as 1 inch in diameter fell in Broomfield and Thornton with 3/4 inch hail measured near Arvada and Hudson and in the city of Denver.

In 2005…severe thunderstorms produced hail as large as 1 inch in diameter in Arvada and the city of Denver.

In 2014…a severe thunderstorm in Lakewood produced hail… up to 1 inch in diameter.

In 2016…a long-lived supercell formed over south Denver and tracked across northeast Adams and continued to produce severe weather as into moved into Yuma County. The length of its path was approximately 121 miles. The storm produced hail up to 1.5 inches in diameter in southeast Denver. As it moved across northeast Adams County…several power poles were sheared off at the base by straight-line winds to 80 mph southwest of Leader. The damage path became more extensive as the storm moved into the northeast plains of Colorado. At Denver International Airport…1.15 inches of precipitation fell which set a new daily precipitation record. The storm produced heavier rainfall on one to two inches east of Denver…with over 4 inches in central Arapahoe County.


In 1996…a late spring snowstorm dumped 4 to 10 inches of snow over the Front Range foothills.  Conifer picked up 10 inches of new snow; Aspen Springs…9 inches; and central city…8 inches.  The sticky…heavy snow clung to power lines and pulled tree branches down…causing power outages to about 1200 homes in the conifer area.  It took up to 6 hours to restore power to some residences. Lightning struck a telephone data cabinet in conifer on the 25th…which knocked out phone service to about 1500 customers.  Widespread rain fell across metro Denver… Where rainfall totaled 2.07 inches at the site of the former Stapleton International Airport and 1.66 inches at Denver International Airport where north winds gusted to 24 mph on the 26th.

In 2010…from the 24th to the 26th…high winds preceding a cold front…swept across the Front Range Foothills and Urban Corridor.  In Aurora…the wind damaged the roof of Rangeview High School.  In Conifer and Denver…the wind downed trees and power lines and caused several brief outages.  The downed power lines also caused several cars to catch fire in the vicinity of 1590 Cook St. in Denver. Peak wind gusts included:  82 mph at Highlands Ranch…67 mph…4 miles east of Franktown and Longmont; 65 mph in Boulder…64 mph in Centennial and Denver International Airport…62 mph near Parker and 60 mph in Arvada.

» Click here to read the rest of May 23 to May 29: This week in Denver weather history

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Thornton sees more precipitation so far in 2021 than in all of 2020

Monday, May 24th, 2021 10:58am MDT
Thornton, Colorado's 2021 precipitation summary through May 24. (ThorntonWeather.com)

Thornton, Colorado’s 2021 precipitation summary through May 24. Click for larger view. (ThorntonWeather.com)

Certainly we are all keenly aware of how wet this year has seemed so far and the numbers back up that feeling.

Every month so far this year has seen above average precipitation (based on 16-year running average) and we have in fact received more precipitation so far this year than in all of last year.

Our current total for 2021 is at 9.86 inches. This is in comparison to the 9.73 inches we received in ALL of last year. This also is nearly 3 inches above our January through May average of 6.94 inches.

These numbers certainly help to ease drought and wildfire concerns. However, Mother Nature can be very fickle and turn off the spout at any moment. We will need consistent, solid numbers throughout the rest of spring and summer to truly put any fears to rest.

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A beautiful spring day starts of Thornton’s workweek

Monday, May 24th, 2021 4:57am MDT

With a healthy dose of sun and temperatures right near normal, we are start off the week in fine fashion.

There is an outside chance some low clouds / fog will move in early but even if they do, it will dissipate later this morning leaving us with sunny skies for the balance of the day. Overall conditions will be calm and dry. High temperatures today will top out right near the average of 75 degrees for the date.

Tonight, skies will be mostly clear with lows in the mid-40s. What does the rest of the workweek hold? See here.

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Thornton’s weekend to remain mild, offer up some wind, a chance for storms

Friday, May 21st, 2021 4:53am MDT

We can look forward to pretty typical weather for this time of year this weekend. We will enjoy nice temperatures but also with some wind and possibly thunderstorms.

For Friday, with a healthy bit of moisture aloft mostly cloudy to partly sunny skies will be above. We will see some breezy winds, mainly in the afternoon into the evening. Look for high temperatures near the 80 degree mark. Tonight, partly clear skies will be above with overnight lows in the low 50s.

Saturday will again see a good bit of cloud cover. It will be cooler with highs in the mid-70s and again, some breezy winds. The afternoon brings just a bit of a chance for a thunderstorm. Saturday night, a few showers / thunderstorms may linger after dark. Overnight lows will again be in the low 50s.

Sunday will see the sun stage a return but, unfortunately, breezy winds will be around for much of the day. Look for highs in the mid to upper 70s. Have a great weekend!

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Very mild temperatures and lots of sun for Thornton’s Thursday

Thursday, May 20th, 2021 4:56am MDT

A fine spring day ahead for us. We will enjoy temperatures well above normal, blue skies and only a slight chance for a storm.

Sunny skies start us off and then we will see a few clouds later in the day but nothing too intrusive. A scattered thunderstorm may develop in the mid to late afternoon but these are not expected to be numerous or strong. High temperatures will be climbing to the upper 80s.

Tonight, skies will be partly cloudy and temperatures will drop to the low 50s.

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Wednesday sees a return of the sun, still will have a chance for thunderstorms

Wednesday, May 19th, 2021 6:05am MDT

Finally! A break from the gray. Today we will enjoy some of that blue above although we may still see an afternoon storm.

Mostly sunny skies start us off with partly sunny conditions being the dominant sky condition for the day. Temperatures today will be warming up nicely and topping out right near the average high for the date of 73 degrees.

The afternoon brings the typical chance for thunderstorms, mainly from 4:00pm to 7:00pm. Any storms that develop should be isolated and not too dramatic.

Tonight, any storm activity will settle down by about 8:00pm. Skies will become mostly clear and overnight lows will be in the upper 40s. Enjoy

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