Thornton, Colorado, USA
UpdatedFri, 27-Nov-2020 2:05pm MST 


ThorntonWeather.com on Twitter

ThorntonWeather.com on Facebook


Weather Geek Stuff - weathergeekstuff.com

Rocky Mountain Weather Network

Tony's Takes Photography


Recent News and Posts

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

Wednesday, August 12th, 2020 2:33pm MST

This Week in Denver Weather History

Denver and Colorado as a whole are known for their unusual weather.  This week in particular is notable for one extraordinary event in weather history – clouds of grasshoppers!


In 1979…heavy thunderstorm rains on each of three consecutive days dumped a total of 2.22 inches of rain at Stapleton International Airport.  The heaviest rain… 0.95 inches…fell on the 9th.  Small hail to 1/8 inch diameter fell on the 8th.


In 1875…clouds of grasshoppers were seen flying through the air on the prevailing winds during each day.


In 1900…a thunderstorm produced west winds sustained to 47 mph with gusts to 55 mph…but only 0.01 inch of rain.

In 1902…a thunderstorm produced no rain and north winds sustained to 52 mph with gusts to 60 mph.

In 1934…heavy cloudbursts in the foothills near Kittredge and at the head of Mount Vernon creek caused flash flooding on both bear creek and Mount Vernon Creek at Morrison… Which resulted in 6 deaths and much property damage. The highway in Mount Vernon Canyon was destroyed by the flood waters.

In 1981…3/4 inch hail fell at Kittredge near Evergreen in Jefferson County.

In 1987…3/4 inch hail fell in Boulder and 9 miles northwest of Castle Rock.

In 1995…lightning struck a 16-year-old counselor in the back of the head while he and a friend were standing under a tree at the singing river ranch…7 miles west of Evergreen.  He stopped breathing…but his friend was able to summon help and they were able to revive him.  He was hospitalized for a few days and released.

In 1998…brief…weak tornadoes (f0) were sighted near Bennett and Roggen.  No damage was reported.  Hail as large as 1 inch diameter fell in Franktown with 3/4 inch diameter hail measured near Castle Rock. Thunderstorm winds gusted to 61 mph near Roggen.


In 2006…mid and high cloudiness overnight on both days resulted in two temperature records.  The low temperature of 71 degrees on the 9th was a record high minimum for the date.  The low temperature of 68 degrees on the 10th equaled the record high minimum for the date first set in 1936.


In 1924…0.01 inch of rain fell over downtown Denver.  This along with the 0.01 inch of rainfall on the 4th was the only rainfall of the month…making this the driest august on record in the city.

In 1962…the high temperature reached 100 degrees at Stapleton Airport.

In 1970…hail stones to 1 inch in diameter were reported in the Fort Lupton area.

In 1972…dry thunderstorm microburst winds gusting to 46 mph briefly reduced the surface visibility to 3/4 mile in blowing dust at Stapleton International Airport.

In 1978…lightning struck two men in Aurora…killing one and injuring the other.

In 1982…a tornado was sighted near Castle Rock and remained on the ground for 10 minutes.  Wind gusts to 60 mph were reported in Castle Rock.  No damage was reported.

In 1994…heavy thunderstorm rains caused flash flooding on Lena Gulch in west metro Denver.  Damage was estimated at 50 thousand dollars.  Lightning struck a house in Westminster…causing a small attic fire.

In 1996…strong thunderstorm winds toppled a tent at a company picnic in Westminster.  Five people received minor injuries when the tent collapsed.  Two cars nearby were also damaged by flying debris.  A weak tornado (f0)…first sighted near Denver International Airport…traveled east to near Bennett and Strasburg.  No significant damage was reported.

In 1998…heavy rain caused flooding and flash flooding problems over southwest metro Denver.  An observer in Lakewood measured 3.26 inches of rainfall in an hour. Several streets were flooded in central Lakewood.  In addition…a trailer park along Lena Gulch in Wheat Ridge was evacuated due to high waters.  One inch diameter hail fell near Roggen.

In 1999…thunderstorm-producing tornadoes…damaging straight line winds…heavy rain…and hail hammered metro Denver.  In the city…small hail and heavy rainfall…up to 2.50 inches an hour…caused a 20-foot by 50-foot section of the roof to collapse at a furniture warehouse.  Damage to the warehouse was estimated at 1 million dollars.  Heavy rain also flooded several underpasses with up to 3 feet of water…which resulted in a number of stalled vehicles.  In Fort Lupton…a tornado bounced across the area.  Spotty damage was reported along a 5-mile path as trees…power poles…and lines were downed.  In addition…an empty semi-trailer was overturned onto another vehicle northeast of the town.  Thunderstorm winds gusted to 81 mph south of Fort Lupton.

In 2004…severe thunderstorms pummeled metro Denver with large hail.  Hail up to 3 inches in diameter was measured 10 miles east of Castle Rock.  Two inch diameter hail fell in Louisville…10 miles north of Hudson…and 1 mile east of Brighton.  Hail to 1.75 inches was reported in Englewood… 1 mile south of Ft. Lupton…and 8 miles east of Boulder. Hail to 1.50 inches was reported around Boulder…near Broomfield…and in Lafayette…Thornton and greenwood village. Hail from 3/4 to 1 inch in diameter was found in Broomfield… Brighton…Castle Rock…Denver and Thornton…and near Longmont… Northglenn…Greenwood Village…Morrison…and Wheat Ridge. Severe thunderstorm wind gusts were recorded to 66 mph in Parker and to 60 mph 5 miles northeast of Boulder.  There were no damage estimates from the hail or wind.

» Click here to read the rest of August 9 to August 15: This week in Denver weather history

Join the Discussion - Post your commentJoin the Discussion!

Wednesday offers yet another hot, dry day of weather in Thornton

Wednesday, August 12th, 2020 4:50am MST

Yeah, we know you are tired of hearing it and we are tired of telling it, but it is what it is. We will once again see mercury readings well above normal with hot and dry conditions today.

Sunny skies start us off and then the afternoon will bring a few clouds. Those clouds won’t do much to inhibit temperatures as we once again will see highs in the mid-90s. No thunderstorms are expected.

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

Join the Discussion - Post your commentJoin the Discussion!

Denver ties record high temperature for August 11

Tuesday, August 11th, 2020 8:33am MST

Record High Temperature

Another hot one and a second high temperature record set in August.

Denver’s high temperature today, as measured at Denver International Airport, topped out at 97 degrees. This ties the Mile High City’s record high for the date last set in 2000.

Thornton matched that reading with a high of 96.7 degrees.

Join the Discussion - Post your commentJoin the Discussion!

The heat returns for Thornton’s Tuesday, conditions remain dry

Tuesday, August 11th, 2020 4:58am MST

Well, yesterday’s very brief break from the heat is gone and today we bounce right back to the mid-90s. Conditions will also remain dry with no appreciable chances for precipitation through the week.

The day starts out with sunny skies but we will then see some clouds arrive. There will also be haze from the Pine Gulch fire on the Western Slope. Highs today will top out in the mid-90s.

Tonight, lows will dip to around 60 degrees under partly cloudy skies.

Join the Discussion - Post your commentJoin the Discussion!

Temperatures near normal Monday as Thornton gets a bit of a break from the heat

Monday, August 10th, 2020 5:13am MST

A one-day respite from the above average temperatures of recent days and those that lie ahead. Today we will see cooler temps with highs closer to normal thanks to a cold front and just a slight chance for a PM thunderstorm.

Mostly sunny skies start us off and will be with us for much of the day. The cold front moved through in the pre-dawn hours bringing some breezy winds that will settle down. The most notable feature will be high temperatures 5 to 10 degrees cooler than what we saw over the weekend. Look for highs today right near the average for the date of 88 degrees.

This evening we may see a few isolated thunderstorms roll through but chances are not great. Mostly clear skies will be above after those settle down and overnight lows will dip to the upper 50s.

Join the Discussion - Post your commentJoin the Discussion!

Denver sets record high temperature for August 9

Sunday, August 9th, 2020 6:26pm MST

Record High Temperature

Our long, hot summer continues and today Denver set a record high temperature.

As measured at Denver International Airport, the Mile High City’s mercury topped out at 99 degrees today. That breaks the old record high temperature for August 9 of 98 degrees set in 2012.

Thornton lucked out and was actually a slight bit cooler today with a high of 97.4 degrees.

Join the Discussion - Post your commentJoin the Discussion!

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

Friday, August 7th, 2020 4:52am MST

One of those weekends where you will want to get those outdoor chores done early in the day. We will be seeing temperatures in the mid-90s through the three-day period with nary a chance for rain.

Friday will bring sunny skies and overall calm conditions. Highs will be in the mid-90s. Tonight, partly cloudy skies will be above with overnight lows in the low 60s.

Saturday brings more of the same. Sunny skies will be the general rules with highs again in the mid-90s. We see just the slightest chance for a thunderstorm in the afternoon. Saturday night into Sunday morning, lows will dip to the low 60s under mostly clear skies Sunday.

Sunday repeats the same pattern from the previous two days. Highs will again top out in the mid-90s with sunny skies above.

Join the Discussion - Post your commentJoin the Discussion!

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

Sunday, August 2nd, 2020 4:52am MST

This Week in Denver Weather History

On first glance our look at this week in Denver weather history appears to be less eventful than many we have looked at previously. However, the severity of the events that appear on the historical weather calendar this week are enough to make you stand up and pay attention. While August is typically a pretty quiet weather month, it is clear that severe weather can certainly strike and Thornton is mentioned in more than one significant event.

From the National Weather Service:


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

In 1911…an apparent dry microburst produced sustained west winds to 42 mph.

In 1972…one workman was killed and another injured when a strong gust of wind destroyed a partially completed apartment building in south Denver. Hail to 1 3/4 inch diameter fell in Golden.

In 1973…hail to 3/4 inch diameter was reported in Boulder.

In 1986…a major outbreak of severe thunderstorms occurred along the Front Range. Thunderstorms developed explosively. Some places were hit by large hail twice. Two inch diameter hail broke car windows on I-25 west of Brighton…and up to 1 1/4 inch hail broke windows in Thornton. Baseball size hail damaged several planes near Watkins. Funnel clouds were sighted around Aurora. Hail over 1/2 inch in diameter covered the ground 3 to 4 inches deep at Hudson northeast of Denver. Most of the hail fell north of metro Denver…but 3/4 inch diameter hail was measured at Stapleton International Airport. Total damage from the hail storms this day was estimated at over 10 million dollars.

In 1991…late afternoon thunderstorms produced heavy rain across metro Denver. Two feet of water covered parts of I-25 in southeast Denver…while one foot of water covered parts of U.S. Highway 285 in Englewood. Thunderstorm rainfall totaled 0.50 inch at Stapleton International Airport.

In 2001…severe thunderstorms producing heavy rain and hail… Either washed out or damaged several County roads in the Watkins and Bennett areas. A small tornado (f0) touched down near Bennett…but did no damage. Hail as large as 1 3/4 inches in diameter fell near Watkins. One inch diameter hail was measured near Hudson and Keenesburg.

In 2008…strong winds blew several trees down in Denver… Damaging homes and downing power lines. A peak wind gust of 67 mph occurred at Centennial Airport…with gusts to 60 mph estimated in Denver. A peak wind gust of 37 mph was measured at Denver International Airport. An elderly man was killed when a wind damaged tree broke free and crushed him while he attempted to remove it. The downed power lines caused outages to about 500 Xcel energy customers.


In 1876…grasshoppers were in great abundance in the city and caused considerable damage to gardens and to crops in the surrounding farms and ranches.

In 1951…heavy thunderstorms rumbled across metro Denver through the night. Heavy rain totaled 3.45 inches at Stapleton Airport. This was the greatest 24 hour precipitation ever recorded during the month of august in Denver.

In 2007…heavy rain caused localized flash flooding near Ft. Lupton. Up to 8 inches of water was reported across County road 18. In addition…several other County roads in the immediate area were washed out.


In 1878…the high temperature climbed to 100 degrees in downtown Denver.

In 1900…a thunderstorm produced west winds sustained to 48 mph with gusts to 55 mph…but only a trace of rain.

In 1903…a thunderstorm produced a trace of rainfall and northwest winds sustained to 45 mph with gusts to 60 mph. The high temperature was 99 degrees.

In 1927…a thunderstorm produced hail and sustained north winds to 22 mph.

In 1933…heavy cloudburst rains caused the failure of the Castlewood dam…which resulted in flash flooding on Cherry Creek…the deaths of 7 people in Denver…and flood damage estimated at 1 million dollars. Lower Denver was flooded during the morning by waters pouring down Cherry Creek and its valley from Castlewood Dam…which had broken between midnight and 2:00 am. Heavy rain of 3 to 9 inches in 9 hours in the watershed above the dam resulted in the failure. At 7:30 am…the flow in Cherry Creek was reported at 16 thousand second-feet as compared with a peak flow of 3 thousand second-feet in other years. The flood waters ruined hundreds of acres of crops and drowned scores of farm animals. Six bridges in Denver were swept away. Great deposits of mud were left in the lower sections of the city…including hundreds of basements and lower floors of buildings. At the end of the month…a deadly stench still rose from swampy areas near the lower city limits.

In 1963…heavy thunderstorm rains in the Parker area caused Cherry Creek to overflow…which damaged roads.

In 1985…a tornado touched down briefly about 10 miles northeast of Parker. No damage was reported.

In 1991…upslope northeast winds produced chilly temperature readings and heavy rain across metro Denver. Rainfall… With no thunder…totaled 1.56 inches at Stapleton International Airport where the heavy rain briefly reduced the surface visibility to 7/8 mile. The mercury climbed to a high of only 63 degrees.

In 1992…a thunderstorm wind gust to 64 mph was recorded in Brighton. A wind gust to 60 mph was measured near the construction site of the new Denver International Airport. Lightning started a fire in an Evergreen church…causing over 75 thousand dollars in damage.

In 1998…3/4 inch hail fell in Jefferson County 15 miles northwest of Arvada.

In 2006…heavy thunderstorm rainfall caused flash flooding along Leyden Creek in unincorporated Jefferson County. An automated rain gauge on upper Leyden Creek…6 miles northwest of Arvada…measured 2.68 inches of rainfall in less than 2 hours. Two to three feet of water covered the roadway at the intersection of 82nd and Quaker Street.

In 2009…a woman riding her bike… In training for an ironman triathlon…was struck by lightning in Boulder. She was in the 78th mile of a 100-mile training ride when she was hit. The woman lost her vision initially and couldn`t move her arms. After a short stay in the hospital…she made of complete recovery.

In 2013…severe wet microburst thunderstorms produced damaging winds and very heavy rain in and around Buckley Air Force Base…Erie and Lafayette. Peak gusts included: 68 mph in Erie…61 mph at Buckley AFB… And 60 mph in Broomfield…4 miles east-southeast of Erie and Lafayette. In Erie…a velodrome under construction was heavily damaged by heavy rain and high winds. The wind toppled the eastern third of the 250-meter cycling track. Bolts measuring one-half-inch thick by 7 1/2 inches in length were ripped out of concrete footers while 16-inch-wide trusses…collapsed under the force of the wind. In town…heavy rain… Around 2.5 inches in less than one hour…caused extensive street flooding. The intense wind also downed trees which resulted in localized power outages. In addition…an empty semi-trailer was blown on its side. A weak non supercell tornado touched down briefly in an open field…7 miles northwest of Hudson. The storm forced seven incoming flights at Denver International Airport to be diverted and contributed to 45-minute delays for others. At Denver International Airport…a peak wind gust of 55 mph was observed from the northeast…with 0.66 inches of rainfall recorded. The very heavy rain produced flash flooding in part of Aurora. Road closures were set up in both directions on both Picadilly Road and Gun Club Road…just north of Buckley AFB. A man had to be rescued when his car was trapped in flood waters at the intersection of 6th Ave. and Picadilly Road. Flash flooding was also observed at the junction of e-470 and I-70 with water running over the road.


In 1988…two inches of rain fell in 3 hours at both Morrison and Wheat Ridge. Thunderstorm rainfall totaled 0.80 inch overnight at Stapleton International Airport.

» Click here to read the rest of August 2 to August 8: This week in Denver weather history

Join the Discussion - Post your commentJoin the Discussion!

Thornton’s weekend to offer up near normal temps, some chances for storms

Friday, July 31st, 2020 5:22am MST

The three day period looks to bring largely typical conditions for this time of year. We will see healthy doses of sun to start each day then the afternoon and evenings bring chances for thunderstorms and showers.

For today, we start out with sunny skies then by late morning a few clouds will gather. Highs will be in the mid to upper 80s. The late afternoon and evening bring just a slight chance for a storm. Tonight, skies will clear and lows will dip to the upper 50s.

Saturday looks similar to today but with better chances for storms. Sunny skies in the AM will give way to some clouds in the PM. Highs will be in the upper 80s. Scattered thunderstorms will be developing in the afternoon and be done in the evening. Saturday night into Sunday morning, lows will drop to around 60 degrees under mostly clear skies.

We close out the weekend on Sunday with the coolest day of the period and better chances for precipitation. Mostly sunny skies will be above until the afternoon and evening. Highs will be in the low to mid-80s. Late morning / early afternoon will see thunderstorms develop with varying chances for activity until after dark. Have a great weekend!

Join the Discussion - Post your commentJoin the Discussion!

Thursday brings cooler temperatures, chance for thunderstorms

Thursday, July 30th, 2020 4:51am MST

A pretty good looking day ahead for Thornton. We will be enjoying lower mercury readings and the afternoon will bring just a chance for storms.

Sunny skies start us off then by mid-morning clouds should start to increase. We do have a good bit of moisture in the atmosphere so if we can get convection going, scattered thunderstorms will develop. Gusty winds will be the biggest threat with these storms. Highs today will top out in the mid-80s.

Tonight, storm activity will end by midnight and skies will clear. Lows tonight will drop to around the 60 degree mark.

Join the Discussion - Post your commentJoin the Discussion!