Thornton, Colorado, USA
UpdatedSat, 25-Sep-2021 7:25am MDT 


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

Sunday, July 4th, 2021 4:57am MDT

This Week in Denver Weather History

As we pointed out in our July weather preview, the month is not only our hottest but it is also the stormiest.  Scorching summer heat is certainly evident when we look back at this week in Denver weather history.  Perhaps more notable is the severe weather we have seen with everything from hail, damaging wind, dangerous lightning and deadly flooding having occurred.


In 2000…the 29th marked the beginning of a near record hot streak for metro Denver.  The high temperatures…as recorded at Denver International Airport…exceeded the 90 degree mark for 17 consecutive days from June 29th through July 15th. The record of 24 consecutive 90 degree or above days was set from July 13th through August 5th…2008.


In 1874…a streak of 18 consecutive days of 90 degrees 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 1874…the temperature reached a high of 102 degrees in downtown Denver.  Large forest fires in the mountains from the west-northwest to the south filled the atmosphere over the city with dense smoke.

In 1885…a thunderstorm produced sustained winds to 44 mph with gusts to 60 mph.  A circus tent was tattered by the strong winds.

In 1900…a thunderstorm produced northwest winds sustained to 42 mph with gusts to 51 mph…but only 0.05 inch of rain.

In 1903…the all time lowest temperature ever recorded in July…42 degrees…occurred. The temperature also occurred on July 31…1873.

In 1910…thunderstorm winds were sustained to 42 mph from the southwest.

In 1922…thunderstorm winds were sustained to 37 mph with gusts to 48 mph.

In 1956…a thunderstorm wind gust to 54 mph was recorded at Stapleton Airport.

In 1964…several men were knocked down by a bolt of lightning while playing golf in south metro Denver.  They got up and ran for cover when one of them was struck by a second bolt. He suffered burns and shock.

In 1987…a weak tornado was observed for 6 minutes…7 miles northeast of Watkins.  Hail 3/4 to 1 1/4 inches in diameter fell in southeast Aurora.

In 1988…lightning struck a group of people at the Jefferson County fairgrounds.  A 42-year-old woman was seriously injured and was hospitalized for 3 days.  Four other people sustained minor injuries.

In 1993…strong northwest winds uprooted several trees across metro Denver.  Wind gusts to 64 mph were reported at Erie north of Denver.  A west wind gust to 43 mph was recorded at Stapleton International Airport.

In 1995…lightning struck and injured two people standing in a field in Arvada.

In 1998…heavy thunderstorm rain…up to 2.75 inches…and marble size hail combined to flood local roads and fields near Roggen.

In 2002…heavy thunderstorm rain in the Hayman Fire burn area caused flash flooding.  In Jefferson County…gulch road was washed out.  In Douglas County…high water washed out some forest access roads as well…generally to the east of a line extending from Signal Butte to Deckers.

In 2010…intense thunderstorms produced torrential rainfall…  in excess of 5 inches in one hour…and caused flash flooding  in the vicinity of Elizabeth.  Numerous county roads were  washed out.  The combination of heavy rain and hail made it  necessary to run snow plows through town.  Extensive  basement flooding was also reported.  Severe thunderstorms  produced large hail from Aurora south to Elizabeth and  Larkspur.  The hail size ranged from 1 to 2 inches in  diameter.  A wet microburst produced 1.84 inches of rainfall  at Denver International Airport.  A peak wind gust to 48 mph  was also observed from the northeast.

In 2017…a microburst produced a wind gust to 61 mph…about 13  miles east-northeast of Denver International Airport.


In 1875…nearly every railroad running into the city was damaged by heavy thunderstorm rains.  The heavy rains washed out wooden bridges over normally dry creeks. Some trains were entirely suspended.  In the city…heavy thunderstorm rain totaled 1.05 inches on the 4th…but only 0.28 inch on the 5th.


In 1989…one of the most intense heat waves on record roasted metro Denver.  The temperature reached 100 degrees or more on 5 consecutive days.  The city had previously never recorded more than 2 straight 100-degree days since records began in 1872.  Water and electricity usage reached all time highs.  The heat wave created extremely dry weather conditions…which contributed to a major forest fire in Boulder canyon on July 9th.  The temperature reached 103 degrees on the 8th…and the mercury climbed to 101 degrees on both the 4th and 5th…and to 102 degrees on both the 6th and 7th.  The low temperature of 68 degrees on the 8th equaled the record high minimum for the date.

» Click here to read the rest of July 4 to July 10: This week in Denver weather history

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Thornton’s July weather preview: Summer heat really kicks in, thunderstorms common

Friday, July 2nd, 2021 6:11pm MDT


Change is of course the one constant in Denver’s weather but come July, things actually get pretty consistent.

The standard formula for a day in July is a sunny morning, clouds developing in the late morning and early afternoon. Come mid-afternoon, thunderstorms are rolling off of the foothills and into the metro area and the eastern plains. These storms do occasionally reach severe status containing hail, gusty winds and heavy downpours of rain.

Check out our July weather preview for a complete look at what is in store for the month ahead.

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Independence Day weekend to offer up near normal temps, some thunderstorms

Friday, July 2nd, 2021 4:42am MDT

Not too shabby of a holiday weekend for Thornton. Temps and conditions are going to be pretty typical for what we expect this time of year.

For Friday, with a good bit of moisture still around, partly sunny skies will be above. Temps will be topping out in the mid-80s. Some PM thunderstorm activity can be expected. Tonight, thunderstorms will end soon after dark and then skies will begin to clear. Overnight lows will be around 60 degrees.

Saturday brings back a good dose of sun for much of the day. Highs climb to around 90 degrees. The afternoon will see some scattered thunderstorm activity. Saturday night into Sunday morning, skies will be mostly clear with lows around 60 degrees.

The Fourth of July brings conditions much like the previous day. Sunny skies will be around early then some PM thunderstorm activity. Highs will again be around 90 degrees. At this time it appears any thunderstorms will be done before dark when the fireworks will begin flying.

Have a fantastic weekend and please be safe!

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Thursday to offer temps near normal, a decent chance for thunderstorms

Thursday, July 1st, 2021 4:59am MDT

The weather for Thornton today looks much like the last couple. We will, however, have a better chance for some PM thunderstorms.

Partly sunny to mostly cloudy skies will be above throughout the day as moisture aloft has increased. High temperatures will be in the low to mid-80s.

A stray, light shower of rain will be possible this morning. The afternoon will bring scattered thunderstorms, particularly in late afternoon / early evening. Brief, heavy rain and gusty winds will be possible.

Tonight, skies remain partly cloudy with a few overnight storms possible. Lows will be in the upper 50s.

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June 27 to July 3: This week in Denver weather history

Thursday, July 1st, 2021 3:04am MDT

This Week in Denver Weather History

Closing out June and entering July our look back at this week in Denver weather history is marked by severe weather and scorching heat.  Damaging hail to dangerous lightning are two common occurrences as is record-setting heat waves.

From the National Weather Service:


In 2002…the maximum temperature in Denver equaled or exceeded 90 degrees for 13 consecutive days…equaling the 5th longest such streak on record.  The record of 18 consecutive days was set during the summer of 1901.


In 1965…wind gusts to 38 mph were recorded in downtown Boulder…causing widespread minor damage.  A microburst wind gust to 41 mph was recorded at Stapleton International Airport.


In 1873…Pikes Peak was hidden from view by smoke from forest fires in the mountains to the southwest of the city.

In 1927…the temperature cooled to a low of only 72 degrees… The all-time record high minimum for the month.

In 1980…lightning injured 4 people on a baseball diamond in Broomfield.  The bolt seriously injured the pitcher while also striking (out) the batter…catcher and second baseman.

In 1987…a microburst wind gust to 53 mph was recorded at Stapleton International Airport.

In 1990…the temperature reached a high of 102 degrees… Setting a new record maximum for the date.

In 1993…thunderstorm winds gusted to 60 mph across parts of metro Denver.  A wind gust to 50 mph blew over a 30-foot canvas tent at an amusement park southeast of Denver. Fifteen people…mostly children…were injured.  Microburst wind gusts to 33 mph were recorded at Stapleton International Airport.

In 2002…heavy rain…up to 3/4 inch…fell across sections of the Hayman burn area near Cheeseman Reservoir.  Several forest service roads were washed out and many culverts were plugged by debris.

In 2004…heavy rain producing thunderstorms caused rock and mud slides across the overland fire burn area in Jamestown. An estimated 50 tons of sand…dirt…rock…and ash slid into town…filling a culvert under main street.  The slide covered 150 to 225 feet of Main Street.  The flood was produced by half an inch of rain in 30 minutes.  A deluge of very heavy rainfall from nearly stationary thunderstorms caused flooding and flash flooding problems over parts of Jefferson and Douglas counties.  An automated rain gage in Golden measured 3.60 inches of rainfall in one hour.  Numerous homes were flooded in Golden…including one that was 146 years old. The home was listed as a complete loss.  State Highway 93 had to be closed from the Pine Ridge subdivision to the Golden Gate Canyon Road.   At the height of the storm…about 4 feet of water covered State Highway 93 through Golden… Forcing its temporary closure.  Several intersections were also flooded and impassable.  Rock and mud slides were reported in Golden Gate Canyon State Park.  At the Deer Creek Golf Course at Colorado 470 and Kipling…the greens were completely inundated by floodwaters.  Some backyards near the golf course were partially washed out.  In Douglas County…water up to a foot deep covered the roadways in Roxborough State Park.  The Waterton Canyon Road also had to be closed due to high water.

In 2010…a severe thunderstorm produced hail up to 1 inch in diameter near Strasburg. Hail up to 3/4 inch in diameter was reported in Aurora and Buckley Air Field.

In 2014…a severe thunderstorm produced hail…up to 1 inch in diameter…near Ft. Lupton.


In 1873…there was a great deal of smoke over the city from forest fires in the mountains.

In 1875…smoke from forest fires in the foothills south of Denver were visible from the city.

In 1913…an apparent dry microburst produced southwest winds sustained to 44 mph with gusts to 48 mph in the city.

In 1925…a thunderstorm produced north winds sustained to 38 mph with gusts to 44 mph.

In 1958…a microburst caused a brief wind gust to 58 mph at Stapleton Airport.

In 1964…lightning struck several homes in metro Denver… Sparking fires.  Some flooding occurred in the stockyards area…at west 45th Avenue and St. Paul Street…and along Harvard Gulch.

In 1997…strong microburst winds of unknown speed downed several trees…signs…and at least one light pole in the Fort Lupton area.  Two trees knocked over by the storm downed power lines causing scattered outages.

In 2002…a thunderstorm wind gust to 60 mph was recorded in Parker.

In 2005…severe thunderstorms produced wind gusts to 66 mph near Longmont and to 60 mph near Niwot.  No damage was reported.  A thunderstorm produced a wind gust to 55 mph at Denver International Airport during the afternoon.

In 2015…a lightning strike injured 15 hikers as they were descending 500 feet below the summit of Mt Bierstadt…in Clear Creek County…south of Georgetown. Eight adults were were transported from the trailhead…and three of those were taken to Denver-area hospitals. One was in serious condition…the other two had non-life threatening injuries. The strike also killed a dog. Severe thunderstorms produced hail up to 1 1/2 inches in diameter…7 miles southwest of Byers…and 1 1/4 inches in diameter…13 miles north of Elizabeth.

In 2016…severe thunderstorms produced hail…from quarter to ping ball size…over northwest…west and southwest parts of Denver. In addition hail up to quarter size was also reported just southeast of Denver International Airport. Officially only a trace of rainfall was measured at the airport…with a peak wind gust of 35 mph from the west.


In 1874…eight different fires in mountain forests were visible from the city.  All of the fires were extensive… And the volume of smoke from each was immense.  Three of these fires had been burning from the 18th with varied intensity.

In 1911…an apparent dry microburst produced sustained winds to 45 mph.

In 1960…a strong gust of wind blew a small foreign sedan off the highway near Brighton…injuring the driver.  East winds gusted to 40 mph at Stapleton Airport.

In 1961…thunderstorm winds estimated as high as 40 to 50 mph occurred over southeast Denver.  No significant damage was reported.

In 1962…heavy rain and small hail caused some flooding in southwest Denver.

In 1995…upslope cloudiness with rain and fog cooled temperatures to record levels.  Low temperature of 47 degrees equaled the record for the date.  High temperature of only 54 degrees set a new record low maximum for the date.  Rainfall totaled 0.90 inch at Denver International Airport and 0.41 inch at the site of the former Stapleton International Airport.

In 2003…a severe thunderstorm in Parker produced hail to 1 inch in diameter.

In 2011…two airmen from the Colorado National Guard suffered minor injuries when they were struck by lightning. They were hit while on duty at a flight line at Buckley Air Force Base. At Denver International Airport…a microburst produced a peak wind gust to 72 mph.


In 1990…almost a year to date after the record breaking heat in early July 1989…the third longest heat wave in Denver history started.  From June 29th through July 2nd the temperature reached 100 degrees or more on four consecutive days.  The highest reading of 102 degrees occurred on the 29th…30th…and 1st.  Combined with the 102 degree reading on June 27th this would have been the longest heat wave on record…but the temperature climbed to only 98 degrees on June 28th.


In 2000…the 29th marked the beginning of a near record hot streak for metro Denver.  The high temperatures…as recorded at Denver International Airport…exceeded the 90 degree mark for 17 consecutive days from June 29th through July 15th. This was one day short of equaling the all time record.  The record of 18 consecutive 90 degree or above days was first set from July 1st through July 18th…1874.  The record was equaled from July 6th through July 23rd…1901.

» Click here to read the rest of June 27 to July 3: This week in Denver weather history

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More warming on Wednesday, another change for thunderstorms

Wednesday, June 30th, 2021 4:57am MDT

Our temperatures slowly continue to climb, getting closer to average for this time of year. Today we also have a bit better chance for a thunderstorm.

Mostly sunny skies start us off this morning. After noon, cloud cover will increase as thunderstorms develop in the high country and foothills and slowly move to lower elevations. High temperatures today will top out in the low to mid-80s. We will have a chance for storms after noon and through the evening.

Tonight, skies will be partly clear with overnight lows in the mid-50s. Some thunderstorms will be possible throughout the night.

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June 2021 top shots: Monthly photo slideshow

Tuesday, June 29th, 2021 6:23pm MDT
A landspout tornado touches down between Firestone and Platteville on June 7, 2021. (Brigette Rodriguez)

A landspout tornado touches down between Firestone and Platteville on June 7, 2021. (Brigette Rodriguez)

The month of June typically sees springtime severe weather reach its height of activity in northeastern Colorado.

This affords the opportunity to capture extraordinary images of amazing weather phenomena from monstrous supercell thunderstorms to heavy rain, hail and even tornadoes.

  • Slideshow updated June 29, 2021

Showcasing images captured by ThorntonWeather.com readers as well as some of our own, our monthly slideshow covers the entire gamut of weather and nature related imagery.

Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted.  June brings some very dynamic weather and the photos are a great way to see the stunning variety.

To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

What is missing in the slideshow above?  Your photo!

Our monthly photo slideshow is going to feature images that we have taken but more importantly images that you have captured.  The photos can be of anything even remotely weather-related.

Landscapes, current conditions, wildlife, pets, kids.  Whimsical, newsy, artsy.  Taken at the zoo, some other area attraction, a local park, a national park or your backyard.  You name it, we want to see and share it!

Images can be taken in Thornton, Denver or anywhere across the extraordinary Centennial State.  We’ll even take some from out of state if we can tie it to Colorado somehow.

We’ll keep the criteria very open to interpretation with just about any image eligible to be shown in our slideshows.

What do you win for having your image in our slideshow?  We are just a ‘mom and pop’ outfit and make no money from our site so we really don’t have the means to provide prizes.  However you will have our undying gratitude and the satisfaction that your images are shared on the most popular website in Thornton.

To share you images with us and get them included in the slideshow just email them to us or share them with ThorntonWeather.com on any of the various social media outlets.  Links are provided below.

So come on, get those camera’s rolling!

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Tuesday temperatures warm up a bit, some thunderstorms possible

Tuesday, June 29th, 2021 5:15am MDT

A pretty good-looking day ahead for Thornton. We will see the mercury climb a few degrees over yesterday but still remain below normal.

This morning will offer up some cloud cover then it will be increasing in the late morning and afternoon. High temperatures will top out in the upper 70s.

The afternoon brings just a bit of a chance for a thunderstorm, mainly from 3:00pm to 6:00pm. At this time, most activity should be to our west and south but we can’t rule out a cell moving into our area.

Tonight, storm activity should end by midnight. Skies will then be mostly cloudy with overnight lows in the mid-50s.

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Comfortable temperatures, a few thunderstorms for Thornton’s Monday

Monday, June 28th, 2021 4:53am MDT

A pretty decent looking day without too much heat. We continue to be under the influence of moist, cool air and that will drive the weather.

Mostly to partly sunny skies will be above throughout the day today. High temperatures will top out in the 70s. Late morning may bring a few sprinkles of rain then the afternoon will see scattered thunderstorms. Most activity will be to our west but we could see a cell or two come our way.

Tonight, a few storms may linger then end by midnight. Lows tonight will be in the mid-50s under partly cloudy skies.

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Lightning and wildfires – Hand in hand hazards

Saturday, June 26th, 2021 6:00am MDT

Wildfires and lightning go hand in hand as half of Colorado’s blazes are ignited by lightning.

Wildfires are not strictly a weather-related threat.  The weather does however play a significant role in starting fires and in the ability of firefighters to battle them.

From the National Weather Service:

500 PM MDT SAT JUNE 26 2021

Colorado Lightning Safety Week concludes today…with wildfires being the final topic.

During the past week we have presented lightning information and safety rules.  Although wildfires are not an actual weather phenomenon…wildfires are directly related to lightning and other weather elements.

Normally…the wildfire threat in Colorado increases significantly after the middle of June and usually peaks in early July…and remains high through august and early September.  Colorado averages about 2500 wildfires each year.

About half of all forest fires in Colorado are ignited by lightning. Additionally…many rangeland and wheat field fires are caused by lightning. Many of these lightning caused wildfires occur in the absence of rain and are the result of what is referred to as dry thunderstorms.

Lightning is often accompanied by strong winds from thunderstorms. These winds can quickly turn smoldering organic material into a raging fire.  Thunderstorm winds tend to be erratic in direction and speed…posing one of the greatest dangers for firefighters.

Lightning that strikes the ground is usually divided into two categories…negative and positive strikes… Depending on the ionic source region of the thunderstorm.  The negative strikes are far more common than positive strikes.  The positive strikes are more intense and have a longer duration than the negative strikes and are more likely to ignite a fire.  Lightning detection technology provides land managers and weather forecasters with the ability to identify the general location and charge category of each lightning strike.

National Weather Service forecasters help land managers and firefighters by producing fire weather zone forecasts on a daily basis.  Spot fire weather forecasts are also provided for those who work on prescribed burns or specific wildfires.  Forecasters also issue red flag warnings for use by land managers when the combination of dry vegetation and critical weather conditions will result in a high potential for the development and spread of

Wildfires.  Land managers…in turn… Typically inform the general public of the fire danger in national parks…forests… And other public lands.

During periods of extreme fire danger in forests and rangelands…

  • You should avoid being in areas where you might become trapped by a wildfire.
  • You should avoid the use of matches or anything else which could ignite a fire.
  • Make sure that hot parts of motorized equipment…such as mufflers…are not allowed to come in contact with dry grasses or other potentially flammable material.
  • If you become trapped or cut off by a wildfire seek shelter in areas with little or no fuel…such as rock slide areas or lakes.

For more information on wildfires and fire safety…please check out the following web addresses…

Lightning Safety and Wildfire Awareness Series:

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