Thornton, Colorado, USA
UpdatedWed, 25-Nov-2020 1:00pm MST 


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Denver ties record high temperature for July 18, Thornton hits 100 degrees

Saturday, July 18th, 2020 6:23pm MST

Record High Temperature

Another toasty day today, and one that was record-setting.

As measured at Denver International Airport, Denver’s official high temperature today topped out at 99 degrees. That ties the record high for July 18 set last year and in previous years.

Here in Thornton, we were actually warmer by one degree hitting 100.1 degrees. This is our first 100 degree reading of the year.

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Thornton’s weekend to offer up hot temperatures, some chances for storms

Friday, July 17th, 2020 4:57am MST

The heat returns in earnest for the first couple of days of the three day period before cooling some on Sunday. Each day offers some chances for thunderstorms with the best opportunity coming at the end of the weekend.

Friday starts out sunny to mostly sunny then we see some clouds increase in the afternoon. Highs today will be in the mid-90s. Isolated thunderstorms will be seen from about 1:00pm to 6:00pm. Tonight, mostly clear skies will be above with overnight lows in the mid-60s.

Saturday will be hottest day of the period with the mercury climbing to the upper 90s under mostly sunny skies. Again, we expect some isolated thunderstorm activity in the afternoon. Saturday night into Sunday mostly cloudy skies will be above with lows in the mid-60s.

A cool front should bring some relief from the heat Sunday and our best chance of the weekend for thunderstorms. Highs will be around the 90 degree mark with chance for thunderstorms in the afternoon and evening.

Have a great weekend!

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Thursday brings a return of the heat, offers just a slight chance for storms

Thursday, July 16th, 2020 4:59am MST

Hopefully you enjoyed the last couple of days of cooler weather because we jump right back into the oven today. Temperatures return to above-normal levels and we have a minimal chance for PM thunderstorms.

Mostly sunny skies start us off and then the afternoon brings the usual increase in cloud cover. High temperatures today will be in the low to mid-90s.

After about 1:00pm and until after dark, there will be some isolated thunderstorm activity. At this time, any that come our way are expected to be high-based with gusty winds being the biggest threat. Tonight, any storms will end by midnight and skies will gradually clear.

Overnight lows will be in the low 60s.

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Thornton to enjoy one more day with cooler than normal temperatures

Wednesday, July 15th, 2020 5:33am MST

We continue our two-day break from the recent heat today. Temperatures will be warmer than yesterday but remain below average.

Partly sunny skies start us off and will be with us throughout the day thanks to a decent bit of moisture being aloft. Highs today will reach the low to mid-80s. The afternoon will, as usual, bring some scattered thunderstorm activity.

Tonight, skies will be partly cloudy with overnight lows around 60 degrees.

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July 12 to July 18: This week in Denver weather history

Wednesday, July 15th, 2020 4:51am MST

This Week in Denver Weather History

A busy week in Denver weather history for sure.  Most notable are the occurences of flooding that seem to happen with regularity as well as the costliest hail storm in American history.


In 1874…a streak of 18 consecutive days of 90 degrees…from the 1st to the 18th…tied for second with another streak that was later set in the summer of 1901. The record of 24 consecutive days was established in the summer of 2008.


In 2012…it was the hottest July on record in Denver since weather records began in 1872. The average temperature for the month was 78.9 degrees which was 4.7 degrees above normal. There were 27 days in which the high temperature equaled or exceeded 90 degrees…which established a new record. There were also 7 days in which the temperature equaled or exceeded 100 degrees which tied the record set in 2005.


In 1901…from the 6th to the 23rd…a streak of 18 consecutive days of 90 degrees tied for second with another streak set in the summer of 1874. The record of 24 consecutive days was established in the summer of 2008.


In 1934…a streak of 15 consecutive days of 90 degrees…from the 7th to the 25th…ranked 5th on the list of hot streaks. The record of 24 consecutive days was established in the summer of 2008.


In 1872…heavy rain from 4:00 pm until 2:00 am caused much damage.  Rainfall totaled 1.76 inches.


In 1881…during the early evening…a brisk rain fell for 30 minutes from a nearly clear sky containing not one tenth of clouds with the sun shining brightly.  Rainfall was 0.16 inch.

In 1885…thunderstorms produced widespread lightning across the city during the evening.  Several people were injured when their homes were struck by lightning.

In 1954…the high temperature reached 101 degrees at Stapleton Airport.

In 1962…lightning struck and killed a Denver man…while he was assisting a co-worker with his car.

In 1971…the temperature climbed to a high of 101 degrees at Stapleton International Airport.

In 1974…hail to 3/4 inch in diameter fell in Castle Rock.

In 1991…hail to 2 inches in diameter fell in Thornton with golf ball size hail in Brighton.  Dime size hail was recorded in the city of Denver.  Very heavy rain caused flooding across metro Denver.  Water was up to 2 feet deep in parts of Golden where one foot of water was reported in the lot of a mobile home park.  Flood water washed away part of a parking lot at the Colorado school of mines in Golden. Heavy rain caused a rock slide and flooding along I-70 in the foothills just west of Denver.  Flood waters were a foot deep at the intersection of I-70 and I-25 just north of downtown Denver.  A funnel cloud was sighted just east of the rocky mountain arsenal.

In 1996…very heavy rainfall from a fast moving thunderstorm dumped 2 to 3 inches of rain within an hour over southern Jefferson County.  Two people were killed near the town of buffalo creek when a 20-foot wall of water flooded the area.  Utility poles and trees were uprooted; cars… Propane tanks…and bridges were destroyed in the flood’s path.  Entire buildings were moved from their foundations and heavily damaged by the floodwaters.  The first fatality occurred along State Highway 126 when the driver of a pick-up truck was washed off the road by the deadly wall of water.  The second death occurred farther upstream when a man in a 5th-wheel trailer was washed away.  This was the second disaster to strike the area in the last couple of months.  The community was already recovering from a wildfire which burned about 12 thousand acres of forest land in late May.  With the forest burned by fire…very little vegetation was available to slow the storm’s runoff…which resulted in the flash flood.  Power…water…and sewer service were heavily damaged in the flood and…in some cases…beyond repair.  The cost of repairing the roads and water system in the area was estimated at around a half million dollars.  Elsewhere across metro Denver…severe thunderstorms produced hail…damaging winds…and small tornadoes.  Weak tornadoes (f0) were reported in Broomfield… 3 miles east of Englewood…and in Dacono.  No damage was reported…except a trampoline was blown into a window and several trees were downed in Broomfield.  Thunderstorm wind gusts estimated as high as 60 mph blew a fence down in Louisville where winds also toppled a tree near a house. The house received only minor damage.  Large hail…strong winds and heavy rain caused substantial property damage in portions of southeastern Boulder and northern Jefferson counties.  Damage estimates in the Broomfield area alone were about 1 million dollars.  Winds gusted to 81 mph in Broomfield.  Large hail…3/4 to 1 1/2 inches in diameter fell in Evergreen…Lakewood…Englewood…Broomfield…near Morrison…northeast of Boulder…and just east of Denver International Airport.

In 2000…heavy rain fell across a portion of the hi meadow fire burn area near buffalo creek…causing localized flooding.  About 3/4 inch of rain fell in 30 minutes over miller gulch.  Some culverts become plugged by debris from the fire.  As a result…small sections of a u.s. forest service road along miller creek were washed out.  Lightning struck a home in Castle Rock…causing extensive damage to the roof…attic…and second floor.

In 2011…severe thunderstorms developed over parts of Adams and Denver counties. At Denver International Airport…a severe thunderstorm produced a peak wind gust to 66 mph… With another gust to 59 mph measured in Denver.  In Commerce City…the intense winds blew down a large tree.


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

In 1910…an apparent dry microburst produced northeast winds sustained to 41 mph.

In 1961…hail as large as 1 inch in diameter was reported near Commerce City.

In 1982…a tornado touched down briefly south of Parker.  No damage was reported.

In 1985…thunderstorms drenched the Highlands Ranch area of northern Douglas County with 1.50 inches of rain in just 30 minutes.  Half an inch of rain fell in 15 minutes in Littleton.

In 1986…a lightning bolt struck a church steeple in Littleton…toppling it to the ground.

In 1989…thunderstorm winds blew down trees and bent a metal basketball fixture just north of Castle Rock in the surrey ridge area.

In 1993…1 inch diameter hail was measured in Lakewood.

In 1995…lightning struck and injured an assistant coach during a baseball game at Highlands Ranch south of Denver.

In 1996…3/4 inch diameter hail fell in Lockbuie with 1 1/2 inch hail measured in Brighton.  Thunderstorm winds gusted to 69 mph at Bennett.  The strong winds were responsible for flipping three semi-trailer trucks onto their sides along I-70…3 miles east of Bennett.  A few cars were also overturned.

In 2001…heavy thunderstorm rain caused flash flooding over south metro Denver.  Three inches of rain reportedly fell near the greenwood village police department in the span of 15 minutes.  The heavy rain caused toll gate creek to overflow…flooding low lying areas along Parker road. Heavy rainfall also caused local flooding along streets near the Denver technology center.  A severe thunderstorm dumped hail to 1 3/4 inches in diameter near Castle Rock.

In 2003…maximum temperature of 100 degrees was a record high for the date.

In 2009…severe thunderstorms produced wind gusts to 70 mph near Parker and Strasburg.  At Denver International Airport…west-northwest winds gusted to 40 mph.

In 2011…severe thunderstorms produced extensive damage as they moved across the urban corridor. At Denver International Airport alone…large hail up to golfball size…very heavy rain and wind gusts to 59 mph caused substantial damage to 40 planes and stranded approximately 1500 passengers overnight. Frontier and United Airlines were hardest hit as dozens of planes were taken out of service for repairs; forcing the cancellation of at least 220 flights over the next several days. Damage to the aircrafts alone was nearly five million dollars. In addition…83 cars in airport parking lots were damaged…  Along with some police cars and maintenance vehicles. In watkins…two people suffered minor injuries and 35 to 40 homes were damaged. As many as two hundred residents in a mobile home park were left homeless by the storm…forcing the Red Cross to open a shelter at Bennett High School. The trailer park contained 52 mobile homes…14 recreational vehicles…3 houses and a commercial building. Hailstones the size of softballs cratered the north sides of the mobile homes. Some farmers in the area said they lost as much as 85 percent of their total wheat crop. Power lines were also damaged which affected about 1200 customers in Watkins. The strong winds also flipped over a tractor- trailer rig on I-70 near Watkins Road. Insurance claims for the Watkins…Bennett and Brighton areas was estimated to be seventeen million dollars. The total damage estimate across the entire urban corridor…was near one hundred sixty five million dollars…and included 17200 automobile claims and 12600 homeowner claims. In addition…thunderstorms producing very heavy rainfall…caused flash flooding in the four mile canyon burn scar west of boulder. Three homes reportedly had water up to the windows with water flowing into structures at Fourmile Canyon Road and Gold Run Road. The heavy rain caused a 4-ft surge along Fourmile Creek through Orodell and into the entry of Boulder Creek. Several roads were affected which restricted access to the area. Roads were closed due to water and debris. Private bridges and drives were washed out and several residents were stranded and later rescued. Numerous cars were damaged in debris flows and several structures suffered flood damage but were not destroyed.


In 2008…a streak of 26 consecutive days of 90 degrees shattered the previous record of 18 consecutive days established in 1901 and 1874.   Ironically…no new single day record high temperatures were set in the month of July. In August however…a record of 104 degrees was set on the 1st…and another record of 103 degrees was set on the 2nd. In addition…a record low min of 70 degrees was set on August 2nd.


In 1878…the temperature reached a high of 100 degrees in downtown Denver.

In 1906…a thunderstorm produced north winds sustained to 52 mph and 0.53 inch of rain in 10 minutes.

In 1912…a heavy thunderstorm cloudburst in the late afternoon combined with a similar storm to the south of the city to produce widespread flooding on Cherry Creek in downtown Denver…which resulted in two deaths and several injuries. The flooding was the worst since 1864 and covered around 3 square miles of lower downtown.  Bridges along Cherry Creek were washed out and water lapped at the floor of the Broadway bridge over the South Platte River…causing authorities to declare it unsafe except for pedestrians.  By nightfall… Union Depot was under 2 to 3 feet of water…and railroad and street car traffic was stalled.  Those forced from their homes by the surging flood waters took refuge in the Denver auditorium.  The flood waters caused great damage to the sewerage system…parkways…bridges and residences and commercial warehouses near Cherry Creek in the wholesale district.  Flood damage was estimated at several million dollars.  Heavy thunderstorm rainfall of 2.00 inches…of which nearly 1.75 inch fell in 30 minutes in central Denver… Was accompanied by severe thunderstorm winds sustained to 55 mph with gusts as high as 74 mph.

In 1933…thunderstorm rainfall was only 0.01 inch…but northwest winds sustained to 37 mph with gusts to 47 mph produced a dust storm for about 10 minutes during the late afternoon.

In 1967…heavy rain flooded areas of north and west metro Denver…and high water closed street intersections in the city.  Crops were damaged…and 200 chickens drowned by flooding northwest of Denver where farm buildings and irrigation facilities were also damaged.

In 1969…a thunderstorm wind gust to 51 mph was recorded at Stapleton International Airport.

In 1975…heavy rains caused locally heavy flash flooding along niver creek south of Thornton and in other parts of north metro Denver.  Over 40 thousand dollars in damage to public property was reported…and numerous homes and yards were damaged.

In 1986…thunderstorm winds blew down a power line in west- central Jefferson County.  The storm…as it moved into Denver…snapped tree limbs and damaged a fence near Washington Park.  Wind gusts in the area were estimated at 80 to 85 mph.

In 1990…thunderstorm wind gusts to 58 mph were recorded at Buckley Field in Aurora.  No damage was reported.  Winds gusted to 44 mph at Stapleton International Airport.

In 1993…a severe thunderstorm moved across southern sections of metro Denver.  Dime size hail fell in Lakewood…and hail up to one inch diameter was measured at Cheery Creek Reservoir.  Later in the afternoon…hail to one inch diameter fell in Golden and Arvada.

In 1994…hail to 1 1/4 inches in diameter fell north of Bennett.

In 1998…dry microburst winds estimated to 70 mph snapped tree branches up to 4 inches in diameter in Brighton where some road signs were twisted and blown down.  At Denver International Airport…dry microburst winds gusted to 61 mph.

In 1995…thunderstorm winds gusted to 62 mph near Strasburg.

In 2001…a severe thunderstorm dumped hail to 3/4 inch in diameter in the foothills about 10 miles northwest of Golden.

In 2011…severe thunderstorms in the Denver metropolitan area produced very heavy rain…large hail and damaging winds. The strong winds toppled a few trees and the heavy rain caused street flooding and minor flash flooding. Several cars were stranded at the intersection of Santa Fe Drive and Oxford…and near Broadway and U.S. Highway 285. A 16-yr old teenager was seriously injured when he tried to retrieve a ball along the banks of West Toll Gate Creek. He was pulled from the swollen creek and died several days later. Hail up to one inch in diameter was reported around the area. The thunderstorms also produced frequent lightning. One strike sparked a fire at Aspen Academy…a private school in Greenwood Village. Most of the damage was confined to the roof and attic. In Englewood…a 40-ft tree was blown into a house and knocked down some power lines. At Denver International Airport…a severe thunderstorm produced sustained winds of 47 mph and a peak wind gust to 68 mph.


In 1985…thunderstorms dumped heavy rain and hail at numerous locations along the Front Range from Denver north.  Some of the heaviest rain fell in northern and western suburbs of Denver.  Up to 2.6 inches of rain drenched Arvada…and Thornton was soaked with 2 inches in 45 minutes.  At least 5 homes in Arvada suffered extensive damage from water and mud…and many streets and basements were flooded.  In southern Jefferson County…11 homes were struck by lightning.

» Click here to read the rest of July 12 to July 18: This week in Denver weather history

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Cold front to bring a very welcome break from the heat Tuesday

Tuesday, July 14th, 2020 5:21am MST

A cold front is pushing through this morning and that is going to finally cool things down. Thornton should see its coolest day in nearly a month.

Mostly sunny skies will start us off but clouds will increase giving us partly sunny skies for most of the day. High temperatures today will top out right near the 80 degree mark, far below the 90s that have dominated recent weeks.

This afternoon and evening some isolated to scattered thunderstorm activity will be seen although most of the action will be to our south and east.

Tonight, partly clear skies will be above with lingering chances for storms. Overnight lows will dip to the mid to upper 50s.

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Another hot one Monday but with some better chances for storms

Monday, July 13th, 2020 4:50am MST

Thornton is going to continue the string of 90+ degree temperatures today. However, with increased moisture aloft we stand a better chance to get some relief in the form of precipitation.

Mostly sunny skies start us off and will be with us for most of the day. There will be a few periods of increased cloud cover as showers and thunderstorms pass.

A few sprinkles could be possible late this morning and then this afternoon scattered thunderstorms will develop and move off the foothills. High temperatures today will top out in the mid-90s.

Tonight, any thunderstorm activity will end not long after sunset then skies will clear. Overnight lows tonight will be around the 60 degree mark.

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Thornton’s weekend weather to offer up hot temperatures, mostly dry conditions

Friday, July 10th, 2020 5:21am MST

The heat is on as we are set to see our warmest weekend of the year so far. Mercury readings around 100 degrees will bookend the three day period with slightly cooler temps Saturday.

For today, sunny skies will be above throughout the day with just a few evening clouds. Highs today will be right near 100 degrees. Tonight, skies will be mostly clear with lows in the low 60s.

A cool front pushes through on Saturday and that will bring some slight relief. Highs will be in the mid-90s under sunny skies with a few PM clouds. Saturday night into Sunday morning, lows will be in the mid-60s under mostly clear skies.

Sunday sees temperatures once again climb and push close to 100 degrees. Mostly sunny skies will be above with the afternoon and evening bringing just a slight chance for a thunderstorm.

Have a great weekend and stay cool! Keep an eye on the temperatures with our live conditions here.

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Thornton’s Thursday continues with the heat, conditions will be calm

Thursday, July 9th, 2020 5:21am MST

No rest for the heat-weary today although while temperatures will again be warmer than normal, they will be a few degrees cooler than yesterday.

The day starts out with sunny skies and those will be with us through the morning. The afternoon will bring a few clouds as usual. Overall conditions will be calm and dry. Highs will reach to the mid-90s.

Tonight, mostly clear skies will be above with overnight lows in the low 60s.

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Unseasonably warm temperatures, calm conditions for Thornton’s Wednesday

Wednesday, July 8th, 2020 5:16am MST

Another day ahead with temperatures well above normal. Conditions will be dry with only some breezy winds in the afternoon.

The day starts out with sunny skies that will be with us through the morning. The afternoon brings a few clouds but nothing too intrusive. High temperatures today will once again top out in the mid-90s.

Tonight, mostly clear skies will be above with lows around 60 degrees.

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