Thornton, Colorado, USA
UpdatedWed, 26-Oct-2016 9:20am MDT 


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The sun finally returns Monday, temps warm up

Monday, May 2nd, 2016 4:59am MDT

It has been a long few days of cloudy, cold and wet weather. Thankfully we break through that pattern starting today.

The workweek starts with a pleasant, but somewhat cooler than normal day. However, it is a big improvement over what we saw this past weekend.

Mostly sunny to sunny skies will be above throughout the day today with light winds. Temperatures will be warming up to the upper 50s. Average for the date is 66 degrees.

Looking ahead, we’ll see temperatures warm up over the next few days with highs pushing the 80 degree mark Thursday and Friday. A bit cooler temperatures and chances for thunderstorms arrive for the weekend.

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April 2016 top shots: Monthly photo slideshow

Saturday, April 30th, 2016 6:17pm MDT
A picture perfect evening in Adams County. (Carolyn Owens Smith)

A picture perfect evening in Adams County. (Carolyn Owens Smith)

April can be a tricky month weather-wise with everything from mild temperatures to snow to severe weather being possible.  The good thing about that is that it provides plenty of chances for great photos!

April marks a transition between winter and summer for most of the country but for Denver it is especially true as we can see a stunning variety of weather.

The proverbial April showers are certainly a possibility for Denver. Snow? Tornadoes? Thunderstorms? You bet – all can happen!

Throw in our usual wildlife plus the wide variety of birds that return to the Centennial State for the spring and summer and there is a lot going on.

  • Slideshow updated April 23, 2016. 
  • To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

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

Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted in images captured from yours and our cameras.

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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Chilly, unsettled weekend weather for Thornton

Friday, April 29th, 2016 5:42am MDT

If you were hoping to work on some of those outdoor spring chores this weekend you might as well hang that list back on the refrigerator and save it for another day. Mother Nature is seeing fit to bring winter-like weather for the three day period with chilly temps and periods of snow and rain.

For Friday we are starting out with some light snow accumulation already and a rain / snow mix falling. The precipitation will continue throughout the day, mostly falling as wet snow. However, much of this will melt quite quickly so actual accumulation won’t amount to much – maybe an inch or two. Highs today will be topping out only in the mid to upper 30s, nearly 30 degrees below normal for the date.

Tonight and overnight periods of rain and snow will continue but with temps increasing a bit, more rain than the white stuff is expected. As we enter Saturday precipitation will become a bit more scattered but possible throughout the day. High temperatures tomorrow will be in the low 40s but feel colder due to some breezy winds that are expected.

Sunday starts out with a wintry mix of rain, snow and possibly some freezing drizzle. By mid-morning less precipitation should be seen but it will remain chilly and cloudy.

Have a great weekend and stay warm.

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Much cooler, showers for Thornton’s Thursday

Thursday, April 28th, 2016 5:30am MDT

Our next storm system arrives today and with it conditions change considerably. Temperatures will be much cooler not only today but through the weekend and we see good chances for precipitation that includes snow.

For today we start out with partly clear skies and those will become mostly cloudy from mid-morning onward. Temperatures will be topping out at only about 46 degrees, a good bit below the average for the date of 65 degrees.

The morning may some sprinkles of rain, perhaps even a snowflake or two mixed in. This afternoon precipitation in the form of rain will increase.

By this evening, rain becomes widespread changing over to a rain / snow mix, possibly all snow, after midnight and into tomorrow morning. We may see an inch or two of accumulation by dawn tomorrow although how much, if any, is going to greatly depend on temperatures.

Get all the latest on our Winter Weather Briefing Page.

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Wednesday remains cool, brings slight chance for showers

Wednesday, April 27th, 2016 5:02am MDT

Unsettled will continue to be the operative weather work for not only today but the foreseeable future. A downward slide in temperatures starts tomorrow and every day will feature varying chances for precipitation.

This morning we woke up to below freezing temperatures and a trace of snow on the deck. We will certainly warm up but highs today will be about 10 degrees below normal. Look for us to top out around 55 degrees.

We’ll have varying degrees of cloudiness above with some sun at times. The afternoon brings a slight chance for showers although they aren’t expected to amount to much.

For the balance of the week, temperatures are going to cool down with Thursday barely making it into the 50s then the 40s to follow for Friday and the weekend. We will continue to have daily chances for rain and thunderstorms with overnight chances for light snow. Get more details in the extended forecast here.

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Cooler temps, showers and thunderstorm for Thornton’s Tuesday

Tuesday, April 26th, 2016 5:49am MDT

A series of days with unsettled weather begins today.  Low pressure, lots of moisture and instability are going to last through the rest of the week into the next.

For today we start out with a bit of sun and will have partly sunny skies for the morning.  This afternoon cloud cover will be increasing as moisture increases as well.

Temperatures today are going to max out in the mid to upper 60s, a bit below the average of 64 degrees for the date.

In terms of precipitation, a few drops may fall during the morning hours but nothing that will amount to much. This afternoon however, activity and coverage will increase.  We will then have a better chance for showers and thunderstorms that will last until about midnight.

Overnight tonight temperatures will be dropping to near freezing and as they do, we may see a snowflake or two in the early morning hours. However, by that time moisture will be decreasing so it isn’t likely much snow, if any, will be seen.

Keep an eye on the sky with our interactive radar here.

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Monday brings warmest day of the week for Thornton

Monday, April 25th, 2016 6:01am MDT

We will enjoy one mild day this week and today is it. After this, it goes downhill with unsettled, cooler conditions for the balance.

Today starts out with mostly sunny skies and calm, mild conditions. Temperatures will be climbing to a high of around 73 degrees, a good bit above the average for the date of 64 degrees.

Winds will be a bit breezy this afternoon and the latter part of the afternoon and into the evening brings a chance for showers and thunderstorms. Right now we expect most of these storms to be high-based and bring primarily wind.

Looking ahead, low pressure is going to reign for the balance of the workweek and through the weekend. Temperatures are going to generally be about 10 degrees below normal and each day will feature opportunities for showers, maybe even just a touch of snow even early tomorrow morning and Wednesday morning. Get a complete look at the extended weather forecast here.

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April 24 to April 30: This week in Denver weather history

Sunday, April 24th, 2016 6:49pm MDT
This Week In Denver Weather History

April 24 to April 30: This week in Denver weather history

Weather in Colorado is always interesting but springtime can bring the entire gamut of conditions. Looking back at this week in Denver weather history we see just how varied this time of year – from flooding rains to heavy snowfall to severe thunderstorms it can and has all happened.

From the National Weather Service:


In 2010…a potent spring storm brought heavy… Wet snow to areas in and near the Front Range Foothills and widespread rainfall across the adjacent plains. In the Front Range Foothills and North-Central Mountains east of the Continental Divide…storm totals ranged from 15 to 30 inches. Storm totals included: 29.5 inches…3 miles southeast of Pinecliffe; 27 inches…8 miles northeast of Four Corners; 23 inches at Willow Creek; 22.5 inches… 13 miles northwest of Golden; 21 inches at Never Summer; 17 inches at Eldorado Springs; 16.5 inches…3 miles west of Jamestown. Denver International Airport reported just a trace of snowfall…but measured 2.01 inches of rainfall for the duration of the storm. In addition…a peak wind gust to 54 mph from the northwest was observed at the airport on the 23rd


In 1883…snowfall totaled 7.6 inches in downtown Denver.

In 1904…a thunderstorm produced hail during the late evening of the 23rd. Apparent post-frontal rain changed to snow during the early morning of the 24th…but totaled only 2.0 inches. Precipitation consisting of rain…melted hail…and snow totaled 0.60 inch. Northeast winds were sustained to 41 mph with gusts as high as 52 mph on the 24th.

In 1905…rain changed to snow and totaled 8.0 inches. Much of the snow melted as it fell with only 2.5 inches measured on the ground. Precipitation totaled 1.88 inches. Northeast winds were sustained to 20 mph on the 23rd.

In 1942…the South Platte River reached flood conditions in the city. As many as 15 thousand residents were warned to evacuate their homes temporarily. Two lives were lost in the city. Four bridges were washed out by the flood waters and other bridges were endangered. The damage was generally limited to bridges that were in poor condition. However…the flood waters did not overflow their channel banks within the city limits.

In 1980…heavy rain began in the eastern foothills on the night of the 23rd and turned to heavy wet snow on the 24th. Up to a foot and a half of snow fell in the foothills west of Denver. At Stapleton International Airport precipitation totaled 1.58 inches…but only 3.7 inches of snow fell from the storm. East winds gusted to 24 mph.

In 1997…locations in and near the foothills received the greatest snow of the year as a winter-like storm system moved into metro Denver. East to southeast winds at speeds of 15 to 35 mph were common with even stronger gusts above 9 thousand feet. Snow fell at a rate of 2 to 3 inches an hour as deep upslope combined with a moist and unstable air mass. The snow began in the foothills above 7500 feet during the evening of the 23rd. By sunrise the snow level had dropped to 5000 feet. The hardest hit areas extended from I-25 into the foothills. Snowfall totals in the foothills ranged from 1 1/2 to over 3 1/2 feet. In the city…snowfall ranged from 8 to 18 inches. Some snowfall amounts included: 36 inches at Coal Creek Canyon; 31 inches at Nederland and Wondervu; 20 to 24 inches near Blackhawk… At Echo Lake…and North Turkey Creek Canyon; 15 to 19 inches at Boulder…central city…conifer…Evergreen…Georgetown… And Louisville; 8 to 14 inches in Arvada…Broomfield… Westminster…Wheat Ridge…Castle Rock…and Ken Caryl Ranch. Only 2.3 inches of snow fell at the site of the former Stapleton International Airport on the 24th. East winds gusted to 36 mph at Denver International Airport on the 24th.

In 2003…a strong and deep northerly flow circulating around a closed upper low pressure center allowed heavy snow to fall in the mountains and eastern foothills. Snowfall totaled 14 inches in Idaho Springs. Rain was mixed with snow and thunder across metro Denver. Snowfall was only 0.9 inch overnight at the site of the former Stapleton International Airport. Precipitation totaled 1.34 inches at Denver International Airport…where northwest winds gusted to 55 mph on the 23rd.

In 2007…a storm system intensified over southeast Colorado… Allowing for heavy snow and rain to develop over much of north-central and northeast Colorado. Severe thunderstorms preceded the storm system on the 23rd…affecting the urban corridor. Nickel size hail was reported in Boulder and a small landspout touched down near Byers. On the 24th…heavy snow fell in the foothills west of Denver and Boulder…where storm totals ranged from 1 to 2 feet. Heavy snow also occurred along the palmer divide…with storm totals of 10 to 16 inches. Elsewhere…a steady moderate to heavy rainfall was reported. Denver International Airport measured 2.09 inches of rainfall…which shattered the previous 24-hr record of 1.29 inches for the 24th of April. The heavy wet snow caused several power outages. In some instances it took several days to restore power. Several road closures were reported…including interstates 25 and 70. A jackknifed semi-trailer backed up traffic for nearly 20 miles…on southbound I-25…between Denver and Colorado springs. In addition…a 50-ton Boulder blocked the southbound lane of State Highway 285…near Parmalee Gulch. Crews had to use explosives to break up the Boulder and clear the debris. Stranded buses and impassable roadways also forced several school closures.


In 1935…heavy wet snow fell across metro Denver. The storm started as rain on the 23rd and changed to snow early on the morning of the 24th. There was continuous precipitation for a period of 48 hours. Snowfall totaled 19.0 inches over the city and 20.0 inches at Denver municipal airport. However… Due to warm temperatures in the 30’s…much of the snow melted as it fell and did not seriously disrupt traffic. The greatest snow accumulation on the ground downtown was 12 inches…but it quickly melted. The highest sustained wind speed recorded during the storm was 28 mph from the north on the 23rd. The storm contained 3.16 inches of moisture.


In 1959…wind gusts to 60 mph recorded in downtown Boulder caused very limited minor damage. West winds gusted to 38 mph at Stapleton Airport.

In 1986…a wind gust to 60 mph was clocked at Golden Gate Canyon.

In 1989…1 3/4 inch diameter hail was reported in Lafayette. Boulder and Louisville reported 3/4 inch hail.
24-25 in 1890…rain changed to snow and totaled 7.0 inches in downtown Denver.

In 1931…heavy snowfall totaled 9.3 inches over downtown Denver. Winds were light during the storm.

In 1996…the second wind storm in less than a week developed east of the continental divide and spread over metro Denver. High winds gusted from 60 to 90 mph. Several power lines and poles were downed. Some of the stronger wind gusts included: 91 mph atop squaw mountain west of Denver…90 mph atop Table Mesa near Boulder…85 mph in Golden Gate Canyon…and 82 mph at Wondervu. Northwest winds gusted to 41 mph at Denver International Airport on the 25th.


In 1924…post-frontal rain changed to snow…which became heavy and totaled 10.2 inches over downtown Denver. The greatest amount of snow on the ground was 6.0 inches on the 25th due to melting. North winds were sustained to 38 mph with gusts to 42 mph on the 24th.


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

In 1908…north winds were sustained to 40 mph behind an apparent cold front. Snowfall was 0.5 inch.

In 1928…rain changed to snow…which became heavy and totaled 7.4 inches in downtown Denver. Due to melting…the maximum snow depth on the ground was 4.0 inches at 6:00 pm. This was the last snow of the season. Southeast winds were sustained to 19 mph with gusts to 20 mph.

In 1976…a south wind gust to 54 mph was recorded at Stapleton International Airport. The high winds toppled a 70-foot high cottonwood tree onto the rear of house and a neighboring residence in central Denver.

In 1989…lightning caused heavy damage to a radio transmitter in Parker…knocking a Denver area radio station off the air for 3 hours.

In 1994…weather spotters reported dime-size hail at the intersection of U.S. Highway 287 and c470 in Jefferson County. Marble-size hail covered the ground near Golden to a depth of 1 inch. Pea-size hail was reported covering the ground to a depth of 3 inches in Arvada.


In 1985…a spring storm brought much rain and snow to metro Denver. The foothills were buried with 15 inches of snow at conifer and 12 inches at Evergreen. At lower elevations… An inch or more of rain fell in Denver and Boulder. The heavy precipitation caused brief power outages in the Denver area. Precipitation totaled 1.06 inches at Stapleton International Airport…including only 0.7 inch of snowfall.

» Click here to read the rest of April 24 to April 30: This week in Denver weather history

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Severe Weather 101 – Severe Weather Awareness Week wrap up

Saturday, April 23rd, 2016 8:30am MDT
Supercell thunderstorms like this can be beautiful - but they can also be deadly. Do you know what to do when severe weather strikes? (Stormscape Photography / FLICKR)

Supercell thunderstorms like this can be beautiful – but they can also be deadly. Do you know what to do when severe weather strikes? (Stormscape Photography / FLICKR)

Over the past week we have highlighted some of the severe weather hazards that we face in Colorado every spring and summer in our Severe Weather 101 series.  The dangers these present are significant and not to be taken lightly.

Tornadoes grab most of the headlines and certainly are a danger however others like lightning and flooding are more common and actually claim more lives.  We ask all of our readers to please, take the time to review these important articles – they could save yours and your family’s lives!

The National Weather Service has published a nice wrap up of Severe Weather Awareness Week that covers all the basics – see it below.  For more in depth information, please use the links at the bottom to view each article on our Severe Weather 101 series.  Be safe and be weatherwise!

600 AM MDT SAT APR 23 2016


Severe Weather Awareness Week in review…

Severe Weather Awareness Week in Colorado concludes today. During the past week we have presented information and safety rules for tornadoes, lightning and wildfires, floods and flash floods, straight-line thunderstorm winds, hail, and our warning programs.

We will now review some of the most important safety rules in our effort to build a Weather-Ready Nation.

Be weather-wise by staying informed on expected weather in your area. The National Weather Service is typically aware of the potential for severe weather many hours or even days before any severe weather watches or warnings are issued, providing forecast products to heighten your awareness. A Weather Story product is posted each day on National Weather Service Internet pages and Facebook pages which includes a map and text on possible hazardous weather expected within the next seven days.

A Hazardous Weather Outlook is also issued daily with information on possible hazardous weather through the next seven days. A watch is issued when conditions for severe weather or flooding become possible. A warning is then issued when life threatening conditions are imminent or occurring.


Tornadoes can even strike in mountain areas. In 2008 on August 23rd, this rope tornado struck Park County near Eleven Mile Reservoir. Image courtesy Jerry Bivens.

Tornadoes can even strike in mountain areas. In 2008 on August 23rd, this rope tornado struck Park County near Eleven Mile Reservoir. Image courtesy Jerry Bivens.

The best way to protect yourself from tornadoes is to have a plan of action. The safest place to be if a tornado approaches is in a basement or safe room within a well-built structure, or in an underground storm shelter. If none of these options are available, move to a hallway or a small interior room on the lowest floor, usually this is a closet or bathroom. Get under a heavy piece of furniture or in a bath tub and cover yourself with blankets. Remember, the greatest risk of injury from tornadoes is from flying debris.

Modular homes and mobile homes, even those tied down, offer little protection from tornadoes. If a tornado approaches, leave those locations and seek safety in a nearby sturdy building or storm shelter.

If you are driving in open country and see a tornado, if time permits, the best thing to do is simply drive away from the tornado path. Do not take shelter beneath a highway overpass. Wind speeds may actually be higher in these areas and often become collection points for debris.

If you are caught outside and cannot seek shelter inside a sturdy structure, crawl into a culvert or lie down in a narrow ditch or ravine and cover your head. But remember that the worst place to be when a tornado threatens is outside in the midst of flying debris.


Lightning usually kills and injures more people in Colorado than any other thunderstorm hazard. Lightning also causes many wildfires.

The best defense to protect yourself against a lightning strike is to plan ahead and avoid being caught where you might be vulnerable. Check weather forecasts prior to venturing out, especially if you are heading into the mountains. Plan outdoor activities early in the day before storms develop.

If thunderstorms threaten, seek shelter in a building or in an enclosed metal-roof vehicle, making sure all windows and doors are closed. Never seek shelter under an isolated tree. During thunderstorms, stay off corded telephones, away from electrical devices, and away from plumbing. Also get out of shower stalls, bath tubs, swimming pools and lakes when lightning is nearby.

You should wait at least 30 minutes after the last sound of thunder before resuming outdoor activities. When thunder roars…go indoors.

Floods and Flash Floods

The Big Thompson Flood in 1976 claimed the lives of 144 Coloradoans and serves to remind us of the dangers of floods. (USGS)

The Big Thompson Flood in 1976 claimed the lives of 144 Coloradoans and serves to remind us of the dangers of floods. (USGS)

When flooding or flash flooding is possible, you should remain alert and be ready to quickly evacuate to higher ground or climb to safety. Flash floods often occur suddenly and without warning. You need to follow some basic flood safety rules:

Do not camp or park your vehicle along streams and washes, particularly during threatening conditions. If you are near a river, be aware of water levels and be prepared to move to higher ground if river levels rise. Do not enter areas that are already flooded. If walking or fishing along a river, be aware that erosion from swift running water can cause river banks to collapse. Never let your children play around high water, storm drains, viaducts or arroyos.

Nearly half of all flash flood fatalities are vehicle related. While driving your automobile, look out for flooding at highway dips, bridges and low areas. Two feet of moving water will carry away most vehicles. Never attempt to drive across a flooded road. And be especially cautious at night when it is difficult to see flood dangers.

Strong Straight-Line Winds

Straight-line winds from thunderstorms, including microbursts, can become quite strong, even reaching speeds in excess of 100 mph in extreme cases. When thunderstorms approach, high winds can suddenly develop, causing things on the ground to become swift moving airborne missiles with a potential force to injure or kill. As with any thunderstorm, seek shelter before the storm arrives.


This is one of the largest recorded hail stones which is more than 7 inches in diameter and fell in Nebraska in 2003. (NOAA)

This is one of the largest recorded hail stones which is more than 7 inches in diameter and fell in Nebraska in 2003. (NOAA)

Large hail can pose a danger to animals and people. Hail also produces considerable damage to crops and personal property each year in Colorado. Again, get indoors before thunderstorms arrive. A fall of small hail can suddenly change to a fall of very large ice missiles which can injure or kill. Make efforts to protect personal property before storms threaten.

Warning Notification

When thunderstorms threaten, tune to NOAA All-Hazards Weather Radio, The Weather Channel, or your local radio or television stations. Also check the Internet web site from the National Weather Service office serving your area. And if you have a relatively new cell phone you should receive Tornado and Flash Flood Warnings on your phone if you are in the area of the warning.

During threatening weather days, plan the actions you will need to take so that you will be prepared if dangerous weather conditions actually develop.

NOAA’s National Weather Service wishes you a safe severe weather season.

Severe Weather Awareness Week in Colorado concludes today. During the past week we have presented information and safety rules for tornadoes, lightning and wildfires, floods and flash floods, straight-line thunderstorm winds, hail, and our warning programs.


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Mild temps, sun to be main feature of Thornton’s weekend

Friday, April 22nd, 2016 5:14am MDT

Last weekend we were beset by a snowstorm, this weekend we see the opposite with very mild temperatures and mostly dry conditions.

We start out the three-day period today with what will probably be the nicest of the batch. Virtually entirely clear skies will be above throughout the day and we will be seeing a high temperature in the mid-70s. Winds will be light, conditions calm.

Saturday as well will be fine day although perhaps just a bit unsettled. Mostly sunny skies will be above and temperatures will be similar to today, perhaps a degree or two warmer. A weak disturbance passing to our north does introduce a slight chance for thunderstorms in the afternoon and evening.

We close out the weekend on Sunday with a bit of a mixed bag. Temperatures will be cooler but still above average for the date. Expect a healthy dose of sun above but also some breezy winds for most of the day.

Have a great weekend!

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