Thornton, Colorado, USA
UpdatedTue, 03-Oct-2023 10:30am MDT 


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Monday brings cool temps, a good chance for showers and thunderstorms

Monday, June 12th, 2023 4:51am MDT

Today’s weather will be similar to what we experienced yesterday but with a better chance for showers. Some of these showers could deliver a heavy dose of rain.

We start off mostly cloudy and the clouds will fill in early leading to cloudy skies for most of the day. High temperatures will top out in the upper 60s. Mid-morning brings a bit of a chance for showers. Afternoon and evening should see showers become widespread and possibly heavy at times.

A Flood Watch will be in effect from 10:00am to midnight due to the swelling of creeks, rivers and possibly flooding in other low-lying areas.

Tonight, some light showers may linger after dark but overall activity will decrease in coverage and intensity. Overnight lows will be around 50 degrees.

Keep an eye out for those showers with our interactive radar here.

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Thornton’s weekend weather to feature its share of storms, end on a cooler note

Friday, June 9th, 2023 4:59am MDT

Mother Nature is set to continue the unsettled weather of recent weeks through this weekend. It starts out mild and somewhat calm but will end cooler and wetter.

For today, we see a day much like the rest of the week has been. Temperatures will be mild with highs near normal. The afternoon brings a typical chance for thunderstorms. Tonight, it will be mostly cloudy with lows in the mid-50s.

Saturday starts out nice with mostly sunny skies. In the afternoon a cold front will make itself felt with increased moisture and better chances for storms. Some of these storms will have the potential to turn severe although the greatest risk for that will be to our east. Highs will be in the mid to upper 70s. Saturday night, we see good chances from rain until about midnight. Lows will be in the low 50s.

Sunday will be a cooler and cloudier day. Look for mostly cloudy to cloudy skies above throughout the daytime hours. Highs will be in the mid to upper 60s. Showers and a few thunderstorms will be possible, particularly in the afternoon.

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Mild temperatures, PM thunderstorms Thursday as same pattern repeats

Thursday, June 8th, 2023 4:51am MDT

Pretty much a copy and paste forecast of recent days. We again will see temps at / a bit below normal and afternoon and evening thunderstorms will be a possibility.

We do expect to see a bit more cloud cover today with mostly to partly sunny skies this morning, then partly clear skies in the afternoon. Morning conditions will be calm and afternoon highs will reach the upper 70s. After noon we expect to see some isolated thunderstorms develop with potential for storms into the evening.

Tonight, any storm activity will end soon after dark. Skies will be partly clear with overnight lows in the mid-50s.


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Wednesday to offer up mild temperatures, typical chance of PM storms

Wednesday, June 7th, 2023 4:55am MDT

The standard late spring / early summer weather pattern for Thornton. We will enjoy a good bit of sun, mild temperatures and the afternoon and evening may bring a round of storms.

Mostly sunny skies start us off then in the afternoon, cloud cover will increase. High temperatures will top out in the upper 70s. Mid to late afternoon will see isolated thunderstorms develop. Gusty winds, brief, heavy rain will be the likely outcome of any storms that appear.

Tonight, some thunderstorms may linger until midnight. After that, skies will see some clearing and lows will dip to the mid-50s.

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Mild temperatures, some thunderstorms for Tuesday

Tuesday, June 6th, 2023 4:44am MDT

A bit nicer day today with mild temperatures and a good bit of sun. As usual, afternoon thunderstorms will develop and bring a chance for wind and rain.

Sunny skies start us off then mostly sunny skies will be the rule for most of the day. High temperatures will top out in the mid to upper 70s. Mid-afternoon will see thunderstorms begin to develop and move off the foothills. Storms will be slow moving and have the potential to bring brief, heavy rain and strong winds.

Tonight, thunderstorm activity will ease after about 9:00pm. Then skies will see some clearing and lows will dip to the low to mid-50s.

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Thornton’s workweek starts off drier than the weekend

Monday, June 5th, 2023 4:50am MDT

A little bit of improvement in the forecast for us. We will see less rain (but there remains a chance for some) and temps should warm up.

Mostly cloudy skies will be the rule throughout the day with an occasional look at blue above. There is still a good bit of moisture to work with so some sprinkles of rain will be possible this morning. This afternoon, chances for rain and thunderstorms increase.

Tonight, shower chances decrease after dark. Overnight lows will be in the low 50s.

What does the rest of the workweek hold? See the extended forecast here.

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June 4 to June 10: This week in Denver weather history

Sunday, June 4th, 2023 2:08pm MDT

This Week in Denver Weather History

The first part of June typically brings some of Denver’s most eventful weather of the year and we clearly see that in our look back at this week in Denver weather history. From many damaging hail and wind events to heavy rains that resulted in flooding and even the Southlands Mall tornado of 2009 it has been an eventful week in history.

From the National Weather Service:


In 1977…unusually warm weather for this early in June resulted in 3 maximum temperature records being equaled at the time: 88 degrees on the 1st…90 degrees on the 2nd… And 93 degrees on the 4th. Maximum of 91 degrees on the 3rd was not a record.


In 2012…it was the hottest June in Denver since weather records began back in 1872. The average temperature for the month was 75.0 degrees which was 7.6 degrees above normal. There were a total of seventeen 90 degree days in the month of June. The highlight of record setting month was a stretch of five consecutive 100 degree days from the 22nd to the 26th. This was only the third time in Denver weather history in which this happened. Two of the high temperatures during the stretch peaked at 105 degrees…which set the all time record for the month of June and tied the all time maximum temperature for Denver.


In 1989…heavy rain drenched metro Denver with the greatest amounts recorded on the 3rd. Total rainfall ranged from 1 1/2 to 3 inches. Roads were washed out in Boulder County… And flooded basements caused water damage to houses in the Gunbarrel section of Boulder. In suburban Denver…heavy rain caused minor flooding along Lena Gulch in Jefferson County where two mobile home parks were evacuated. Rainfall totaled 1.66 inches at Stapleton International Airport.


In 1921…heavy rainfall for nearly a week…on top of streams already swollen by mountain snowmelt…produced widespread flooding over the South Platte River basin…including the tributaries through the canyons to the west and southwest of Denver. Heavy rainfall over the 6-day period totaled 3.36 inches in Boulder…4.98 inches in Morrison…4.27 inches in Castle Rock…and 2.94 inches in the city of Denver. Rainfall amounts in the foothills were estimated between 3 and 6 inches. The narrow-gage tracks of the Colorado and southern railroad were destroyed in the Platte Canyon. From the mouth of the canyon through the city to near Brighton… The river spread from 1/2 to nearly 1 1/2 miles wide… Flooding farm and pasture land and destroying or damaging many bridges. In the city…many businesses along with as many as 500 homes were inundated…forcing their evacuation. Bridges were swept away. The high waters flooded the rail yards and stock yards in lower downtown…closing three adjacent packing houses. The heavy rains also caused flooding on Boulder creek in Boulder on the 6th.


In 1904…a thunderstorm during the early morning of the 3rd turned into widespread general rain…which continued into the early afternoon of the 4th. Rainfall totaled 2.04 inches.


In 1878…a “waterspout” or cloudburst of rain was sighted up the South Platte canyon at around noon. The resulting high waters on the South Platte River slightly damaged a railroad bridge in the city.

In 1937…a trace of snow fell in downtown Denver where rainfall totaled 0.25 inch. Minimum temperature of 34 degrees was a record low for the date. Northeast winds were sustained to 22 mph.

In 1951…the start of the second shortest snow-free period on record…109 days…occurred with the last snow of the season…a trace…on the 3rd. The first snow of the next season occurred on September 21st when 4.2 inches of snow fell at Stapleton Airport.

In 1954…a microburst produced brief sustained winds of 40 mph with gusts as high as 64 mph at Stapleton Airport.

In 1956…the failure of the Georgetown dam caused downstream flooding on clear creek at Idaho Springs and Golden.

In 1976…funnel clouds were sighted near Brighton…Erie…and Dacono…all north of Denver. A tornado touched down briefly 1 1/2 miles east of Lafayette. Another tornado touched down briefly at Hyland Hills Golf Course in Westminster. No damage was reported.

In 1983…severe thunderstorms during the afternoon produced 3/4 inch hail in south Denver…golf ball size hail 5 miles west of Parker…1 1/4 inch hail in Littleton…1 1/2 inch hail in south Aurora.

In 2001…hail as large as 1 inch in diameter fell 17 miles north of Bennett in Adams County.

In 2005…snow was mixed with rain for nearly an hour at Denver International Airport during mid to late morning. The temperature at the time was 45 degrees. Precipitation totaled 0.36 inch for the day. Northwest winds gusted to 37 mph.

In 2008…a severe thunderstorm produced large hail…up to 1 3/4 inches in diameter in Arvada…a northwest suburb of Denver. Several vehicles were damaged. In addition…a severe thunderstorms produced hail to 1 inch in diameter… 10 miles northeast of manila…east of Denver International Airport.

In 2015…severe thunderstorms broke out across Boulder… Denver…Elbert…Jefferson and southern Larimer Counties. Two large and long lived tornadoes developed near Berthoud and near Simla. The tornado that occurred along the Boulder and Larimer county line.  It first touched about 3 miles south of Berthoud…and then tracked to the west/northwest and lifted about 6 miles southwest of Berthoud. The majority of the damage was EF1…with some areas of EF2… and a few small areas of EF3. At least 25 homes between Longmont and Berthoud were damaged; three of them destroyed. No injuries were reported as the winds tore apart homes and rolled vehicles. The EF3 rating is defined as maximum winds estimated at 135 to 140 mph. The path length was 6 miles long with a width of one quarter mile at times. Large hail from quarter to tennis tennis ball size was observed.  The largest hail occurred in northeast Boulder County. The hail damaged cars and homes; breaking windows and windshields.  In addition… numerous roads were closed along the Larimer and Boulder county line due to flash flooding. Just west of Berthoud… 3.47 inches of rain had fallen.  At Denver International Airport…only 0.01 inches of rainfall was recorded… with a peak wind gust to 35 mph from the northeast.

In 2020…severe thunderstorms produced intense wind gusts across parts of Adams and Denver counties.  A peak wind gust of 64 mph was observed near Bennett…with a gust to 58 mph observed at Denver International Airport.


In 1965…lightning and an 18-hour rain storm damaged streets and roads and telephone and power lines across metro Denver. Precipitation totaled 2.77 inches at Stapleton International Airport where the visibility was reduced to 3 miles at times from pre-frontal thunderstorms and heavy upslope rains.

In 1998…a late season snow storm struck the Front Range foothills. Up to 5 inches of snow fell in Coal Creek Canyon. Light snow also fell over western sections of metro Denver and briefly at Denver International Airport. Snow covered the grass at the Denver federal center in Lakewood before melting around mid-morning on the 5th. No snow fell at the site of the former Stapleton International Airport. Several temperature records were set. High temperatures of 47 degrees on the 4th and 49 degrees on the 5th were record low maximums for their respective dates. Minimum temperature of 34 degrees on both the 5th and 6th were record lows for those dates.


In 1864…high water on the west fork of clear creek caused a small dam near empire to fail…which destroyed several downstream bridges.

In 1885…a windstorm during the afternoon and early evening produced south to southwest winds at sustained speeds up to 42 mph.

In 1937…a trace of snow fell in downtown Denver. This was the latest snowfall of record at the time. Light rain and snow were mixed around mid-day. Precipitation totaled only 0.01 inch. North winds were sustained to 20 mph.

In 1941…hail of unknown size fell on the city.

In 1961…lightning struck and injured an airman outside a base classroom at Lowry Air Force Base. Funnel clouds were sighted near Frederick and firestone north of Denver. The one near Frederick briefly touched down in an open field but caused no damage. Heavy rain and hail hit the Fort Lupton area causing damage to crops. Heavy rain in Frederick added to the flood damage of the 3rd. A pilot reported a funnel cloud that touched down briefly and then dissipated south of Castle Rock.

In 1965…a lightning-caused fire destroyed a mountain home near Rollinsville.

In 1988…a tornado touched down 5 miles east of Lafayette near I-25 and stayed on the ground for 15 minutes. The twister hit a campground…demolishing one trailer and damaging six others…along with 4 cars. The rope-like funnel also blew down fences…signs…and electrical boxes. The twister moved a 1500-pound hay wagon 150 feet. Total damage to the campground was estimated at 50 thousand dollars. Another tornado touched down between Broomfield and Lafayette…staying on the ground for about 20 minutes. The twister hit a subdivision…unroofing one abandoned house and causing minor damage to a dozen others. A four- car garage and three barns were destroyed. At one location a chain link fence…a satellite dish…and a shed were destroyed…while the deck and garage of the house were damaged. A grain storage tank was moved 200 feet. There were reports of boards being blown through walls; one came through a kitchen.

In 1992…lightning struck a 15-year-old boy…causing minor injuries…in Adams County 6 miles north-northeast of Stapleton International Airport. Thunderstorm winds gusted to 63 mph at Jefferson County Airport near Broomfield…to 58 mph at the U.S. Atomic Energy Commission’s facility at Rocky Flats…to 58 mph in Thornton…and to 48 mph at Stapleton International Airport where 1/8 inch diameter hail fell.

In 1996…strong microburst winds up to 60 mph damaged several trees in Boulder…snapping large branches 1 to 2 inches in diameter.

In 1997…a woman was struck by lightning as she was walking to her car in Nederland. The lightning bolt apparently struck a nearby power line and arced into her left hand. She received minor injuries.

In 2014…severe thunderstorms broke out across parts of Arapahoe…Douglas…Elbert and Jefferson Counties… impacting areas generally southwest and south of Denver. The storms produced large hail…from quarter to golfball size.

In 2015…severe thunderstorms produced hail up to 1 1/2 inches in diameter in Castle Rock and hail up to 1 inches in diameter…southwest of Byers.  At Denver International Airport…0.99 inches of rainfall was recorded. A peak wind gust to 35 mph from the southwest as also observed.

In 2017…an intense thunderstorm produced damaging downburst winds which snapped a power pole near the interchange of Interstate 70 and US 36. A weak short-lived landspout also touched down south of I-70 near Bennett and tossed around some lawn furniture.


In 1977…lightning caused several power outages and moderate damage to a railroad building.


In 1954…thunderstorm winds at speeds of 50 mph with gusts as high as 59 mph briefly reduced the visibility to 1 mile in blowing dust at Stapleton Airport.

In 1967…the public reported golf ball to 1 3/4 inch diameter hail in the city…3 miles west-southwest of Stapleton International Airport. The amount of damage was unknown. Thunderstorm winds gusted to 46 mph at Stapleton International Airport.

In 1981…hail to 3/4 inch in diameter was reported in east Denver.

In 1990…golf ball size hail was reported near Strasburg on I-70 east of Denver.

In 1991…a tornado was spotted by national weather service personnel and weather spotters…14 to 17 miles northeast of Stapleton International Airport. A funnel cloud was sighted over south Aurora just east of Buckley Field…and a tornado was spotted just east of Watkins. No damage was reported. Thunderstorms moved through Aurora and dropped hail up to 1 inch in diameter. The storms also produced heavy rain… Up to 1 inch in 30 minutes…causing flooding of streets. Water was reported hood deep…stranding motorists. Water covered fire hydrants at some intersections.

In 1995…a waterspout sighted over Standley Lake in northern Jefferson County…quickly dissipated once it reached shore. A brief tornado…which was momentarily visible by a dust debris cloud on the ground…damaged the roof of a house in Westminster. A funnel cloud was sighted just south of Lafayette. Hail from 3/4 to 1 1/4 inches in diameter fell over north Boulder. Thunderstorm outflow produced north wind gusts to 44 mph at Denver International Airport.

In 1997…a tornado touched down near baseline reservoir just east of Boulder. The tornado struck a home…tearing off part of the roof. A storage building nearby was nearly leveled and 5 trees were uprooted. The twister then moved onto baseline reservoir…forming a huge waterspout. Several recreational vehicles and a boat dock were also damaged. A nearly stationary line of thunderstorms dumped 4.60 inches of rain on portions of Thornton. Extensive flooding of streets and underpasses and other low lying areas was reported. Several businesses were flooded and basements in the area were damaged. Rainfall totaled 1.02 inches at Denver International Airport and 1.24 inches at the site of the former Stapleton International Airport. Large hail…up to 1 3/4 inches in diameter…fell over the city of Denver with 3/4 inch hail measured in Littleton and near Henderson.

In 1999…high winds developed for a brief time in and near the foothills of Boulder. The Gamow Tower on the University of Colorado campus recorded a wind gust to 87 mph. Winds peaked to 71 mph atop Niwot Ridge near the continental divide west of Boulder.

In 2003…a small tornado touched down near Strasburg…but did no damage.

In 2012…severe thunderstorms broke late in the evening…striking areas hardest from Denver southward. Locations impacted by the storms included but were not limited to: Aurora…Castle Rock…Centennial…Highlands Ranch…Lone Tree…Parker and Surrey Ridge. The storms produced a barrage of
large hail…damaging straight line winds…flash flooding and several short lived tornadoes. The hail ranged in size from 1 to 2 inches in diameter…and caused extensive damage to homes and automobiles. The hail inundated the roadways with several inches of hail in Douglas County. Consequently…snow plows had to be called out to clear the roadways. The combination of torrential hail and heavy rain produced flash flooding in parts of Elbert…Douglas and Arapahoe Counties…as thunderstorms brought up to 3.35 inches of rain to some areas within 90 minutes. In Aurora…Picadilly Road was closed from flooding north of 6th Avenue. A water rescue took place on South Gun Club Road in Arapahoe County…where floodwaters were rushing to depth of 3 feet. Flash flooding forced the closure of several streets and roads from Parker south to The Pinery…where the floodwaters inundated the roadway with up to 2 feet in several locations.  At Centennial Airport…a historic B-17 Flying Fortress suffered extensive damage as hailstones as large as ping pong balls struck the aircraft. Although the airframe itself did not require repair…the fabric-covered ailerons and elevators were extensively damaged. The hail came straight down and punched holes in the fabric-covered control surfaces. The aircraft landed just hours before the storm hit to participate in a weekend tour stop.  Lightning also struck two homes…one in Lakewood and the other in Parker. Straight line winds downed trees and power lines in Aurora. As a result…scattered electrical outages affected around five thousand residents.  At Denver International Airport…0.61 inches rainfall was recorded along with a peak wind gust of 41 mph.

In 2016…powerful thunderstorms fired up along the Urban Corridor and produced damaging hail…strong outflow winds… heavy rain and lightning. Golf-ball size hail in Highlands Ranch caused extensive damage including broken windows on homes and windshields on vehicles. Heavy rainfall…also produced street flooding. In and around Highlands Ranch… anywhere from 2.3 to 2.8 inches of rainfall was observed… with 1.0 to 1.5 inches around metro Denver.  At Denver International Airport…0.38 inches of rainfall was recorded.

In 2020…a combination of an upper level trough moving northwest across the state…coupled with a strong surface pressure gradient…led to numerous reports of high wind gusts across the Denver the surrounding region. Most of the wind damage occurred with the passage of a rare derecho; a large fast-moving complex of thunderstorms with powerful straight-line winds. In addition…strong wind gusts from 59 to 71 mph not associated with the derecho… occurred prior to and following the passage of this system. By midday the derecho…moved over the mountains…and then rapidly northeast across the I-25 corridor by mid afternoon. Wind gusts from 60 to 80 mph were common with a few gusts exceeding 90 mph. The highest gust observed was 110 mph…at the Winter Park Ski area…around 12000 feet. Xcel Energy reported more than 208000 customers lost power because of the storm statewide. Widespread tree damage was reported. The intense wind toppled a billboard that crashed onto Denver bakery. Two delivery trucks parked nearby were heavily damaged. Two injuries occurred in Denver…one seriously. A man and his nine-year-old daughter were injured by a fallen tree. They were standing in front of a family member’s house when the incident occurred. The tree impaled the father through his back and he required several surgeries. His daughter sustained cuts and bruises that required stitches.  Southwest winds gusted to 78 mph at Denver International Airport…with a peak gust to 76 mph at Centennial Airport.


In 2004…a brief hot spell produced 3 temperature records. High temperatures of 95 degrees on the 6th and 98 degrees on the 7th were record maximum temperatures for the dates. Low temperature of 68 degrees on the 7th was a record high minimum for the date.

In 2007…an unusually strong storm system brought very strong winds to the Front Range foothills and urban corridor. Peak gusts included: 92 mph at Boulder…85 mph…2 miles southwest of Boulder…83 mph…10 miles south of Boulder and 55 mph at Denver International Airport. High winds forced the closure of Mt. Evans road and Trail Ridge Road. Several trees were uprooted across the urban corridor. In Aurora… The driver of a car was injured when some building material blew off the Fitzsimmons Complex. The debris landed on the car and knocked the driver unconscious. The wind forced the cancellation of 60 flights at Denver International Airport. Xcel reported outages in Boulder…Denver…Lakewood and Longmont. » Click here to read the rest of June 4 to June 10: This week in Denver weather history

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May 28 to June 3: This week in Denver weather history

Sunday, May 28th, 2023 2:08pm MDT

This Week in Denver Weather History

There are many notable events on our look back at the weather history books for this week but one in particular stands out. It was 36 years ago this week, on June 3, that the infamous Thornton tornado struck. This twister still stands as the most damaging tornado to have ever struck the Denver metro area.


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.


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.

In 2019…a severe thunderstorm broke out over metro Denver during the overnight hours. Some damage was reported to cars and vegetation. The hail ranged in size 7/8 inch to 1 1/4 inch in diameter. Broadcast media reported damage to 16 different greenhouses around Denver; seven experienced significant damage. In addition…two separate storms passed across Denver International Airport. The hail accumulated on the runways but no damage to aircraft was reported.


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.


In 1894…heavy rain combined with snowmelt runoff caused widespread flooding over the South Platte River basin. Rainfall was heaviest in the foothills where 5 to 8 inches were measured over the 4 days. Heavy rainfall west of Boulder flooded mining towns and damaged mining properties. In the canyons above Boulder…railroads and roads were washed out along with many bridges. The floodwaters spread into central Boulder and covered a wide area from University Hill north to near Mapleton Hill to a maximum depth of 8 feet. Many houses were swept away…and every bridge in Boulder was destroyed. A few people…trapped in their homes by the floodwaters… Had to be rescued. However…the gradual rise of the flood waters resulted in only one death. Boulder creek spread to a width of nearly one mile in the pasture land to the east of Boulder. Extensive flooding on left hand creek north of Boulder washed away railroad and wagon bridges. The heavy cloudbursts caused flooding on bear creek…which washed away bridges…railroad tracks…and structures and destroyed the canyon roadway. Morrison sustained the heaviest flood damage on bear creek. In Denver…rainfall totaled only 1.50 inches on the 30th and 31st…but the heavy rainfall on upstream tributaries of the South Platte River caused the river to rise as much as 10 feet above the low water mark in the city…which caused some flooding of pasture land downstream to a depth of 6 feet near Brighton.


In 1875…a windstorm lasting almost all day produced sustained winds to 42 mph.

In 1935…southeast winds sustained to 29 mph with gusts to 34 mph produced a moderate duststorm during the afternoon.

In 1938…heavy thunderstorm rain and hail pummeled downtown Denver during the evening hours. Rainfall accumulated to 1.63 inches. Hail accumulated to a depth of 18 inches.

In 1948…a localized thunderstorm caused flooding on sand creek in Aurora and northeast Denver. Rainfall was only 0.49 inch in downtown Denver where light hail also fell.

In 1963…a golfer died of injuries received when struck by lightning on a golf course southwest of Denver. A warehouse in Denver was damaged and its contents destroyed by a lightning-caused fire.

In 1967…up to 4.00 inches of rain in Lakewood and wheat ridge caused flooding of roads and basements. Water was several feet deep in some yards. Many streets were temporarily closed. Hail as large as 1 inch in diameter fell in Wheat Ridge. Hail piled up to 2 feet deep in some low lying areas of east and southeast Denver. Snowplows were employed to remove the hail. Stapleton International Airport…where west winds gusted to 39 mph…received 1.51 inches of rain and hail…which forced the closure of the runways for an hour. Hail stones to 3/4 inch in diameter were measured at Buckley Field. A funnel cloud was sighted near south Wadsworth Blvd and Bear Creek. A tornado touched down briefly in the vicinity of 60th and 62nd avenues near north Washington Street. The storm uprooted trees and damaged one building. Doors were ripped from a business house…widely scattering irrigation pipe. In addition…a total of 3 funnel clouds were sighted in that area.

In 1970…hail up to 1 inch in diameter fell at Stapleton International Airport.

In 1976…a single thunderstorm crossed south metro Denver producing a funnel cloud 2 miles south of Arapahoe road and Broadway. The storm moved over Buckley Field producing a funnel cloud and 1/2 inch diameter hail. As the storm moved northeast of the city…a large tornado touched down near east 59th Ave and tower road and was on the ground for 20 minutes. It demolished a 60-foot-long cinderblock cow shed…tore a wall from a machinery shed…tore shingles off the roof of a farmhouse nearby…and felled 12 trees on one farm. A boy in a feed shed 20 feet from a destroyed building was not injured.

In 1977…3/4 to 1 inch diameter hail fell at or near Stapleton International Airport. One inch to baseball size hail fell in south Denver…damaging some homes and extensively damaging some airplanes at Arapahoe County airport…now centennial airport. Hail covered highways to a depth of 6 to 8 inches in south Denver.

In 1978…two funnel clouds were sighted 5 miles south of Stapleton International Airport. Hail up to 1 1/4 inches in diameter was reported in wheat ridge and northwest Denver. Only 1/2 inch diameter hail fell at Stapleton International Airport.

In 1989…golf ball size hail fell at the junction of I-25 and I-225. One inch diameter hail fell in Littleton.

In 1990…a line of severe thunderstorms crossed metro Denver… Producing wind gusts to 60 mph and scattered areas of pea to marble size hail. Small trees and branches were blown down by the strong thunderstorm winds…which also caused minor power outages across southern and eastern sections of metro Denver. The strong winds uprooted a 25- to 30-foot tree in the acres green subdivision of northern Douglas County. The tree blocked a busy street for several hours. A pilot reported hail as large as 1 1/2 inches in diameter covering the ground near the north end of a runway at Stapleton International Airport. Heavy rain caused a rock and mud slide that partially closed the Boulder canyon highway 10 miles west of Boulder. Thunderstorm winds gusted to 41 mph at Stapleton International Airport.

In 2001…lightning ignited a fire which destroyed a luxury home on bear mountain near Evergreen. Estimated damage was set at 1 million dollars.

In 2003…flash flooding occurred in the Hayman Fire burn area after as much as 1 inch of rain fell in 30 minutes. The heavy rainfall washed out many access roads and closed State Highway 67 between Deckers and west creek. A 3-foot wall of water ran down Fourmile Creek from the YMCA camp at Shady Brook…damaging one building in the camp and flooding roads. Hail as large as 3/4 inch in diameter fell near Roggen in weld County.

In 2005…lightning struck as least 20 homes in Westminster. Only minor damage was reported. Severe thunderstorms produced hail as large as 1.25 inches in and near Fort Lupton and hail to 3/4 inch near Indian Hills in Jefferson County.

In 2014…heavy rainfall…nearly 1.2 inches in 30 minutes… produced localized street flooding in Boulder. The heavy rain coupled with the already swollen creeks from the spring runoff along Boulder Creek resulted in the flooding. Street flooding was reported at 6th St and Canyon Blvd and at Baseline Road. Some cars were stranded in the high water in low lying areas and one person reported being trapped in his vehicle.


In 1935…heavy thunderstorm rains overnight caused flash flooding east of the city on both Kiowa and Bijou Creeks… Resulting in a total of 9 deaths. Most of the damage was on Kiowa Creek where there were more structures. The water rose rapidly during the storm…ripping houses and stores from their foundations and sweeping them downstream. Precipitation in Denver totaled only 0.01 inch. Hail fell in the city for a short time. The hail was very small and caused no damage.

In 1983…a late storm of rain and snow hit the Front Range. Over an inch of rain fell at some spots…and above 7 thousand feet…1 to 5 inches of snow whitened the ground. Some snowflakes even fell in the western suburbs of metro Denver on the night of the 30th.

In 2002…unseasonably warm weather at the end of the month resulted in 3 temperature records. High temperature of 91 degrees on the 30th equaled the record maximum for the date. Low temperature of 61 degrees on the 31st was a record high minimum for the date. High temperature of 93 degrees on the 31st was a record maximum for the date.


In 1917…rainfall totaled 0.55 inch and was mixed briefly with snow around midday. Only a trace of snow fell. Cold temperatures during the day resulted in a high of 44 degrees and a low of 35 degrees. The month closed as the coldest May on record with a mean temperature of only 48.7 degrees…about 8 degrees below normal. The cold temperatures during the month had a marked effect on shade trees and shrubs in the city. Elms were just starting to leaf. Leaves on cottonwoods and maples were only half formed. Lilacs were just blooming…and snowball clusters would not bloom for days.

In 1959…the public reported a tornado briefly touching the ground 10 miles south of Stapleton Airport. No damage was reported.

In 1984…a thunderstorm microburst produced a wind gust to 67 mph…7 miles east of Boulder.

In 1991…hail to golf ball size pummeled southern and southeastern sections of metro Denver and continued on east to Watkins. Several houses and cars were damaged. Later… Thunderstorms dumped heavy rain across the city of Denver… Causing street flooding in an area just south of downtown and just northwest of downtown. Water was up to 10 inches deep over northwest Denver. A brief tornado touched down in Castle Rock where 3/4 inch diameter hail also fell.

In 1993…thunderstorms dropped dime size hail in Commerce City.

In 1994…lightning struck an apartment in Louisville and damaged electronic equipment…including a computer.

In 2006…a severe thunderstorm produced 1 inch diameter hail near Boulder.


In 1875…a windstorm during the late afternoon and early evening produced sustained winds to 50 mph.

In 1898…south winds were sustained to 41 mph with gusts to 46 mph.

In 1917…a trace of unmelted snow fell in downtown Denver. Precipitation for the day totaled 0.08 inch…half of which was estimated to be from melted snow.

In 1919…snowfall of 0.4 inch was measured in downtown Denver. This was the greatest calendar day and 24-hour snowfall ever recorded during the month of June. Precipitation (rain and melted snow) totaled 0.15 inch. Two temperature records were set. The low temperature of 32 degrees was a record minimum for the date. The high temperature of only 40 degrees was a record low maximum for the date and the month. North winds were sustained to 36 mph with gusts to 40 mph.

In 1951…a trace of snow fell at Stapleton Airport.

In 1961…hail as large as 1 1/2 inches in diameter fell in west Denver with hail to 1 1/4 inches reported in derby.

In 1965…a man struck by lightning in southeast Denver died shortly after being admitted to a hospital. Lightning damaged power lines in east and southeast Denver.

In 1980…strong thunderstorm winds blew in the windows of a mobile home in Northglenn.

In 1990…a thunderstorm produced wind gusts to 63 mph in Boulder. A small tornado touched down in a farmer’s field between the towns of Louisville and Lafayette. Another tornado was spotted in an open field 3 miles west of Brighton. A funnel cloud was sighted near Hudson. A microburst wind gust to 55 mph was recorded at Stapleton International Airport. No damage was reported from any of these events.

In 1991…severe thunderstorms producing large hail…damaging winds…funnel clouds…and heavy rain were widespread across metro Denver. Funnel clouds were reported in Lakewood… Boulder…Arvada…and just east of the rocky mountain arsenal. Hail up to golf ball size fell in Lakewood…just west of Sedalia…in Littleton…Arvada…Englewood…and the city of Denver. A mobile home park in Jefferson County reported hail to 3 feet deep. Up to 1.00 inch of rain fell in 45 minutes near Boulder…causing Boulder creek to flow out of its banks. Rock and mud slides forced the closure of many roads in Boulder County. Later in the afternoon thunderstorms produced rainfall amounts of 2 to 3 inches over a couple of hours. Clear creek in Golden spilled over onto U.S. Highway 6. Heavy rains washed away part of a bridge near Erie. Water was up to 18 inches deep in Westminster. Wind gusts to 58 mph were reported at Stapleton International Airport where 1/4 inch hail fell… And heavy thunderstorm rainfall totaled 0.82 inches…briefly reducing the visibility to 1 1/4 miles. Estimates of total damage from these storms would exceed 7 million dollars.

In 1994…hail up to 1 inch in diameter fell over south Denver and Littleton.

In 1997…two short lived-tornadoes formed near Bennett…but did no reported damage.

In 2002…strong winds from the outflow of dissipating showers developed to the east of Denver. Near Strasburg…a spotter recorded a wind gust to 58 mph.

In 2019…severe thunderstorms produced large hail from 1 to 1 3/4 inch hail east of Centennial and over southeast Aurora. » Click here to read the rest of May 28 to June 3: This week in Denver weather history

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Out of the office taking a break

Friday, May 19th, 2023 4:00pm MDT

Out of the Office and in the Mountains

Time for a break! We will be largely incommunicado for a couple of weeks as we take a break and disconnect from the online world to rest and recharge. In the meantime, be sure to visit the website regularly for the latest forecasts, radar, current conditions and more. Don’t worry, we will return.  😉  See you soon!

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Thornton’s weekend starts cloudy and cool, will then warm up and dry out

Friday, May 19th, 2023 4:53am MDT

The three day period starts out a little bit less than ideal with clouds and some sprinkles of rain. Hang in there though as the balance of the weekend will be warmer, sunnier and drier.

For Friday, cloudy skies will be above and highs will only be in the mid-60s. Some sprinkles of rain will be possible throughout the day. Tonight, any showers will end by midnight and the skies will begin to clear. Lows will be in the mid-40s.

Saturday looks to be pleasant with mostly sunny skies and highs in the mid-70s. The afternoon brings just a slight chance for a thunderstorm. Saturday night, partly cloudy skies will be above with lows around 50 degrees.

Sunday will be much like Saturday but a few degrees warmer. Highs will be in the mid to upper 70s with the usual chance for a thunderstorm. Have a great weekend!

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