Thornton, Colorado, USA
UpdatedThu, 20-Sep-2018 5:15am MDT 


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Thornton’s Tuesday to offer near normal temps, a chance for storms

Tuesday, September 4th, 2018 5:01am MDT

The short workweek gets started with weather similar to what we saw this past weekend. We do however stand a better chance to see some storms this evening.

The day starts out with mostly sunny skies but then cloud cover will increase leading to partly sunny skies for most of the daytime. Winds will be light initially then just a bit breezy this afternoon as a weak front pushes through.

Temperatures will be topping out in the low 80s. Late afternoon brings a slight chance for a thunderstorm and showers. This evening chances increase for us to see some activity.

Overnight tonight, there may be some isolated showers lasting into tomorrow. Lows tonight will be in the mid-50s.

Keep an eye out for the showers here.

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August 2018 weather recap: Month sees cooler than normal temps, well below normal precipitation

Saturday, September 1st, 2018 4:44pm MDT

Somewhat of a mixed bag for Thornton’s weather in August.  While we enjoyed temperatures near normal without too many extremes, precipitation was lacking considerably from what we expect during the month.

The month started out toward the cool side but with days of above normal temps interspersed.  For the first few weeks it appeared we would end up a good bit cooler than normal but then the heat returned for much of the last week driving up average temperatures.

Precipitation was quite disappointing with only a couple decent rainfalls during the month and a few minimal events.

Probably the most notable thing for the month was the relatively persistent haze from smoke from wildfires to our west.  While it made for pretty sunrises and sunsets, it obscured our normally beautiful blue skies.

Thornton finished the month with an average temperature of 70.4 degrees.  That is more than two degrees cooler than Denver’s long term August average of 72.5 degrees. As is the norm, Denver’s official measurement came in a good bit warmer with an average of 72.4 degrees.

Our highs ranged from a maximum of 94.9 degrees on the 4th of the month down to a low of 47 degrees on the morning of the 20th.  Denver matched our maximum on the same date and saw a low of 46 degrees on the 20th which also tied the record low for the date.

The month saw a paltry 0.52 inches fall in Thornton’s rain bucket.  Denver actually fared better with 0.93 inches.  Both measurements however fell short of the August average of 1.69 inches.

Click here to view Thornton’s August 2018 climate report.

Thornton, Colorado's August 2018 temperature summary. (ThorntonWeather.com)

Thornton, Colorado’s August 2018 temperature summary. (ThorntonWeather.com)

Thornton, Colorado's August 2018 precipitation summary. (ThorntonWeather.com)

Thornton, Colorado’s August 2018 precipitation summary. (ThorntonWeather.com)

318 PM MDT SAT SEP 1 2018




                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
 HIGH             105   08/08/1878
 LOW               40   08/26/1910
HIGHEST            95   08/04       105     -10       95  08/19
LOWEST             46   08/20        40       6       51  08/04
AVG. MAXIMUM     86.8              87.2    -0.4     85.7
AVG. MINIMUM     58.0              57.9     0.1     57.3
MEAN             72.4              72.5    -0.1     71.5
DAYS MAX >= 90     11              11.5    -0.5       10
DAYS MAX <= 32      0               0.0     0.0        0
DAYS MIN <= 32      0               0.0     0.0        0
DAYS MIN <= 0       0               0.0     0.0        0

 MAXIMUM         5.85   1979
 MINIMUM         0.02   1924
TOTALS           0.93              1.69   -0.76     1.86
DAILY AVG.       0.03              0.05   -0.02     0.06
DAYS >= .01         7               8.6    -1.6        6
DAYS >= .10         2               4.3    -2.3        4
DAYS >= .50         0               1.2    -1.2        2
DAYS >= 1.00        0               0.3    -0.3        0

 24 HR. TOTAL    0.38   08/14 TO 08/14

 TOTAL            0.0
 TOTAL            0.0               0.0

HEATING TOTAL       9                10      -1        8
 SINCE 7/1          9                16      -7        8
COOLING TOTAL     247               244       3      216
 SINCE 1/1        862               688     174      749

 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05

AVERAGE WIND SPEED              10.3

AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR           12
NUMBER OF DAYS PC             17


THUNDERSTORMS             9   MIXED PRECIP           0
HEAVY RAIN                1   MODERATE RAIN          3
LIGHT RAIN               12   FREEZING RAIN          0
LT FREEZING RAIN          0   HAIL                   0
HEAVY SNOW                0   SNOW                   0
LIGHT SNOW                0   FOG W/VIS <=1/4 MILE   2
FOG                       4   HAZE                   8

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August 2018 top shots: Monthly photo slideshow

Friday, August 31st, 2018 4:40pm MDT
Black and white of a scene in Thornton. (LE Worley)

Black and white of a scene in Thornton. (LE Worley)

As the calendar turns to August, the summertime heat begins to fade and that makes it easier to get out and enjoy all of the outdoor activities Colorado has to offer.  From a walk in a park to afternoon thunderstorms to an abundance of wildlife, photo opportunities abound as is seen in our slideshow.

Our monsoon season typically arrives about now and that means better chances for moisture.  However with limited instability, the intensity of storms are more sedate.  That doesn’t mean however that the weather is any less photographic.

  • Slideshow updated August 31, 2018

By the end of the month some of our seasonal feathered friends will be looking to leave the state giving our last chance to see them till spring.  Larger mammals are gearing up for the rut (mating season) and that can make for some intense scenes.

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.

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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Thornton’s Labor Day weekend starts toasty but then cools down

Friday, August 31st, 2018 4:29am MDT

We have one more day of unseasonably warm temperatures. A cold front will then arrive and serve to cool things down for the balance of the holiday weekend.

For Friday, we will enjoy mostly sunny skies for the daytime. Temperatures will be quite warm again with highs in the low 90s. The afternoon and evening bring just a slight chance for storms any that do develop should only bring light rain and some wind.

The cold front backs in tonight and that means changes for the rest of the period. Saturday will again have mostly sunny skies but highs should be in the low 80s. We do stand a bit better chance for storms as well.

Sunday looks much like Saturday. A good bit of sun should be above with highs again in the low 80s. Just a slight chance for PM storms.

Labor Day continues with more of the same with similar highs as the previous two days and a slight chance for storms.

Have a great holiday weekend!

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Thornton’s Thursday to offer up hottest temps of the week

Thursday, August 30th, 2018 4:49am MDT

Another hot day for us today with temperatures nearly 10 degrees above normal. We will have some additional cloud cover due to mid-level moisture but that won’t do much to keep the mercury from climbing.

The day starts out with mostly clear skies. This afternoon, look for cloud cover to increase. Right now it looks like we will remain dry today with only a slight chance of some gusty winds from high-based storms. Highs today will top out in the low to mid-90s.

Tonight, skies will be partly clear with lows to the low 60s.

Tomorrow we expect to see another unseasonably warm day then things cool a bit for the weekend. Details here.

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Sunny, calm, unseasonably warm conditions for Thornton’s Wednesday

Wednesday, August 29th, 2018 5:08am MDT

As yesterday’s cold front slips away, high pressure returns to northeastern Colorado. This will result in increasing temperatures and calm, dry conditions.

The day starts out with sunny skies that will last through the morning. A few clouds will arrive this afternoon but nothing intrusive. Overall conditions will be calm and we don’t expect to see any storms in our area. Temperatures will top out in the upper 80s, perhaps hitting the 90 degree mark.

Tonight, skies remain mostly clear with lows in the mid to upper 50s.

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Cold front ushers in cooler temperatures Tuesday, brings slight chance for showers

Tuesday, August 28th, 2018 5:17am MDT

Following yesterday’s very warm temperatures and wind, Thornton gets a nice break today. We will be nearly 20 degrees cooler and see just a slight chance for storms.

The day starts out with mostly sunny skies and will have more of the same for much of the day until mid-afternoon when a few more clouds arrive.

The cold front that moved through early this morning will help limit highs today to the mid-70s. The mid to late afternoon through the evening brings just a slight chance for some showers / thunderstorms.

Tonight, skies will clear and lows will be in the low to mid-50s.

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August 26 to September 1: This week in Denver weather history

Monday, August 27th, 2018 9:53am MDT
This week in Denver weather history

August 26 to September 1: This week in Denver weather history

Significant events on Denver’s weather history calendar get a bit less numerous as we enter what is historically a relatively quiet period of the year. That isn’t to say however that major weather events can’t occur. Our look back at this week in Denver weather history includes a massive hail storm in 1944, many events in which lightning injured people and the warmest temperature ever recorded in September.

From the National Weather Service:


In 1875…grasshoppers appeared in great numbers at 10:00 am on the 19th. Thousands landed on the ground. The streets were literally covered with them. Swarms of grasshoppers were seen on each day. All gardens in the city were devastated…and in the countryside the grasshoppers were very destructive to ripened grain. On the 30th the grasshoppers were so numerous as to almost darken the sun.


In 1910…the lowest temperature ever recorded in August…40 degrees…occurred on each of these days and on August 22… 1904. The unusually cold weather for so early in the season brought sub-freezing minimum temperatures to much of the Colorado northeastern plains.


In 1944…one of the most destructive hailstorms in the city in a decade caused damage estimated at nearly one million dollars. The storm occurred within a period of 10 to 30 minutes…between 2:00 pm and 3:00 pm. The hail varied in size from very small to as large as 1 1/2 inches in diameter. Hail covered the ground to a depth of 5 to 6 inches in some sections of the city. Several people were cut by broken glass. The hail and heavy rain flooded underpasses to a depth of 6 feet…and the occupants of stalled autos had to be rescued. Sewers were unable to handle the sudden amount of water and water backed up and flooded a number of basements. A few first floors of buildings were flooded. The water department had a busy time replacing manhole covers that had been displaced by the water pressure. Trees were stripped…one was severely broken…and telephone lines were downed. Roofs…windows… automobiles…awnings…and gardens were severely damaged. Flowers and gardens in some sections of the city were a total loss. Greenhouses were extensively broken with an estimated 20 carloads of glass shattered. Vegetable and truck crops in and around the city were severely shredded. The next day the American Red Cross was designated by the war agency to grant any and all priorities needed to obtain materials and supplies to replace and repair the damage. In downtown Denver…the thunderstorm produced 0.95 inch of rain and heavy hail along with sustained northwest winds to 25 mph.

In 1961…strong winds blew in the walls of a warehouse under construction in Denver. Two workmen suffered a fractured foot and body bruises.

In 2014…two men in central Denver were struck by lightning as they sat under a tree to avoid a heavy downpour. One of the men was unconscious and had no pulse when emergency responders arrived. He was immediately taken to Denver Health was listed in critical condition. The other victim suffered less severe injuries. He was treated at the scene and hospitalized…then released a few hours later.


In 1980…two heavy thunderstorms hit Arvada and Westminster… Dumping up to 1.50 inches of rain in less than an hour. At least two streets were washed out and a number of homes and cars were damaged when a creek flooded. Three homes in Arvada sustained minor lightning damage.


In 1910…a thunderstorm produced south winds sustained to 40 mph.

In 1961…strong thunderstorm winds and heavy rain occurred at 79th and federal blvd. In Westminster. The strong winds blew the roofs off lumber sheds onto parked cars.

In 1967…a young woman was killed by lightning while horseback riding in the suburbs just west of Denver. Her horse died several hours after the incident. A young man and another young woman were also knocked from their horses by the impact of the lightning and required hospitalization.

In 1991…heavy thunderstorm rainfall totaled 0.91 inch at Stapleton International Airport…where 1/4 inch diameter hail was measured.

In 1996…localized street flooding occurred in the Fort Lupton area when 2 to 3 inches of rain fell in 45 minutes. The roof of a community college began leaking…which caused damage to ceiling tiles. The roof was under repair from hail damage which had occurred earlier in the summer. A weak tornado (f0) was sighted near Fort Lupton. No damage was reported.

In 1999…a slow moving thunderstorm dumped 5 inches of rain in 2 hours near Dacono. A severe thunderstorm produced 3/4 inch diameter hail in Castle Rock.

In 2002…severe thunderstorms spread large hail over metro Denver. Hail as large as 2 inches in diameter fell in Jefferson County 5 to 11 miles northwest of Golden. Other large hail reports included: 1 1/2 inches near Golden and in Lakewood; 1 1/4 inches in Nederland; 1 inch hail near Elizabeth…Louviers…Rollinsville…and Blackhawk; 7/8 inch hail near Acequia in Douglas County. A thunderstorm produced a trace of rain and a microburst wind gust to 52 mph at Denver International Airport.

In 2003…lightning struck a house and sparked a fire in Arvada. Damage to the roof and ceiling was extensive.

In 2005…lightning struck an unoccupied home in Parker. The resulting fire damaged the roof…attic…and second floor bedroom. Damage was estimated at 15 thousand dollars.

27-28 » Click here to read the rest of August 26 to September 1: This week in Denver weather history

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Thornton’s workweek starts with lots of wind, unseasonably warm temperatures

Monday, August 27th, 2018 5:18am MDT

Another day with temps a good bit above normal and dry conditions. We will also be throwing in a good bit of wind that will lead to heightened fire danger.

The day starts out with mostly sunny skies and those will continue throughout the day. Temperatures today will be topping out close to the mid-90s, nearly 10 degrees above normal for the date.

The biggest story is going to be the wind. It started blowing early and will continue through the day and not settling down until near sunset. Gusts to 40+ mph will be possible.

The wind coupled with low humidity and dry fuels have prompted a Red Flag Warning to be issued for the elevated fire danger. Caution should be exercised.

Tonight, winds will ease and skies will remain mostly clear. Overnight lows will dip to the mid-50s.

Keep an eye on the temps and wind speeds here.

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Thornton’s Friday and weekend to feature unseasonably warm temps, overall calm conditions

Friday, August 24th, 2018 5:01am MDT

A pretty decent looking three-day period ahead for us. Temperatures will be warmer than normal throughout but storm activity will be very low.

For Friday, sunny skies start things off then we may see a few clouds this afternoon. Like yesterday, smoke is expected to create haze later in the day. Temperatures will top out in the low 90s. Tonight, partly cloudy skies will be above with lows near 60.

Saturday will continue the unseasonably warm weather but with highs a degree or two cooler than today. There will be more cloud cover as moisture aloft increases. Tomorrow evening gives us just a slight chance for a thunderstorm. Overnight Saturday into Sunday, skies will clear some and lows again will be near the 60 degree mark.

The weekend closes out on Sunday in fine fashion. Mostly sunny skies will be above with highs right near 90 degrees.

Have a fantastic weekend!

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