Thornton, Colorado, USA
UpdatedThu, 20-Jan-2022 6:45am MST 


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

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

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 MST

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 MST

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 MST

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 MST
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 MST

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 MST

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 MST

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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Thornton’s weekend to bring relief from the heat, some good chances for precipitation

Friday, June 25th, 2021 5:08am MST

Well, I would prefer this type of weather happened during the week but we will take what we can get at this point. Look for things to cool down quite a bit this weekend and, with any luck, we will get some wet stuff from the sky.

For Friday, partly sunny skies will be above with highs in the mid-70s. Some sprinkles will be possible this morning then the afternoon brings a decent chance for showers and thunderstorms. Overnight, skies remain partly clear with lows in the mid-50s. Some showers and thunderstorms may persist.

Saturday continues the trend with partly sunny skies and temps cooling a bit further. Winds will be breezy in the afternoon. Some light rain showers and a thunderstorm or two will be possible. Saturday night into

Sunday morning, a few, lingering showers may be seen. Overnight lows will be in the mid-50s. Sunday look much like the previous two days. Partly clear skies will be above with highs in the low 70s. Some showers and thunderstorms will be possible.

Have a great weekend!

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When lightning strikes – Rendering aid and the lasting effects of a strike

Friday, June 25th, 2021 3:00am MST
Lightning strike (NOAA)

Responding quickly to lightning strike victims is key to helping them survive. (NOAA)

Knowing what to do when lightning strikes someone is critical to helping them survive.  As with many serious injuries, immediate action must be taken.  After the event, lightning strike victims oftentimes face a number of health and mental challenges.

From the National Weather Service:

600 AM MDT FRI Jun 25 2021

Colorado Lightning Safety Awareness Week continues through tomorrow. Today we discuss lightning medical issues for survivors.

The facts about lightning strike victims:

In Colorado, nearly a half million cloud-to-ground lightning flashes are documented each year. With millions of visitors and extensive outdoor activities, it is not surprising that, each year on average, three people are killed by lightning in the state of Colorado while 13 are injured. Last year, two people were killed by lightning in the Centennial State while seven were injured.

While any lightning fatality is tragic, injuries caused by lightning can be devastating to both the victim and the family. For those who have a family member or relative that suffers a significant disability from lightning, life changes forever. In addition to the physical pain and mental anguish suffered by the victim and their family, the incident may lead to a loss of income for all involved as medical expenses can drain the family’s financial resources.

If someone is struck by lightning, it is critically important that they receive the appropriate medical attention immediately. Some deaths can be prevented if the victims are attended to promptly. Lightning victims do not carry an electrical charge and are safe to handle. First, check to see that the victim is breathing and has a pulse, and start cardio-pulmonary resuscitation, if needed. Then have someone dial 911. If possible, move the victim to a safer place. Do not let the rescuers become lightning victims. Lightning can strike the same place twice.

Lightning strike victims may face many mental challenges that they will have to live with for the rest of their lives. When the brain is affected by a lightning strike, the person often has difficulty with many of the mental processes that most people take for granted. The person may suffer from short-term memory loss, and may have difficulty remembering new information and accessing old information. Victims may often find it very difficult to carry on more than one task at a time, and may be easily distracted. Their personality may change and they may become easily irritated.

Lightning strike victims often become easily fatigued and may become exhausted after only a few hours of work. This may be because mental tasks that were once automatic may now require intense concentration to accomplish. Although some victims may sleep excessively at first, after a few weeks many find it difficult to sleep more than two or three hours at a time.

Another common long-term problem for survivors is pain.

Medically, pain is difficult to quantify. Lightning strike victims often suffer irreparable nerve damage that causes intense pain that affects the ability to function. Many survivors complain of chronic headaches, some of which are very intense and debilitating.

Lightning Strike and Electric Shock Survivors International is a support group for individuals and families that are struggling with life after a lightning injury. Helpful information is available at their web address: www.lightning-strike.org

In addition, NOAA’s lightning website contains abundant information on lightning safety and can be found at: www.lightningsafety.noaa.gov

Lightning information specific for the State of Colorado can be found at: www.weather.gov/pub/lightning

The lightning topic for tomorrow will be lightning caused fires.

Lightning Safety and Wildfire Awareness Series:

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