Thornton, Colorado, USA
UpdatedWed, 16-Jan-2019 10:20pm MST 


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A very nice late summer weekend in store for Thornton

Friday, September 7th, 2018 5:17am MST

With two weeks until fall begins, we are down to the closing days of summer and Mother Nature is going to give us fine looking few days. Temperatures will start out a bit cooler than normal but then warm up nicely to above normal levels.

For Friday, the day starts out with some fog in a few spots. That will lift early and we will have some cloud cover initially but then this afternoon will bring mostly sunny skies. There is just the slightest chance for an isolated storm in the late afternoon but most likely we won’t see any activity. Temperatures will top out in the mid to upper 70s. Tonight, skies will be partly clear with lows in the mid-50s.

For Saturday, the weather looks to be absolutely perfect for Thornton’s Harvest Fest. Mostly sunny skies will be above and we expect to remain dry with calm conditions. High temperatures should reach to the mid-80s. Saturday night into Sunday morning, skies will be partly clear with lows to the mid to upper 50s.

Sunday is the Denver Broncos’ season opener and those of you heading to the game will find shorts and t-shirts are all the attire you need. Mostly sunny skies will be above and highs will be in the mid to upper 80s. Sunday night, once again, partly cloudy skies will be above with lows to the mid-50s.

Have a great weekend, Thornton!

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September 2 to September 8: This week in Denver weather history

Thursday, September 6th, 2018 2:05pm MST
This week in Denver weather history

September 2 to September 8: This week in Denver weather history

Normally September is a relatively quiet month however we do occasionally see some extraordinary conditions. Our look back at this week in Denver weather history shows the earliest seasonal snowfall in Denver history, damaging lightning and the destruction of the Fourmile Canyon wildfire.

From the National Weather Service:


In 1995…record breaking heat occurred on the first 5 days of the month when the temperature climbed into the 90’s on each day. Record high temperatures of 97 degrees on both the 1st and 4th equaled the all-time record maximum for the month. High temperature of 95 degrees on the 3rd was a record for the date. High temperatures of 94 degrees on both the 2nd and the 5th were not records. The low temperature of 64 degrees on the 4th equaled the record high minimum for the date.


In 1978…the temperature reached 90 degrees or more on seven consecutive days with the highest temperature…94 degrees… Recorded on both the 4th and 6th.


In 1938…heavy cloudbursts in the foothills near the top of Genesee Mountain caused flash flooding on Bear Creek at Morrison. Nearly 8 inches of rain fell just north of Morrison in 6 hours and drowned 6 people in a car between Morrison and Kittredge. Damage was estimated at nearly a half million dollars. Flash flooding also occurred on south Boulder Creek in Eldorado Springs. Rainfall totaled 4.42 inches in Eldorado Springs…and rainfall was estimated to more than 6 inches in the foothills west of the town. Many buildings and residences were damaged in Eldorado Springs…and bridges were swept away. The high waters forced residents from their homes as far downstream as Erie. This was the flood of record on South Boulder Creek.

In 1973…hail to 3/4 inch diameter was reported in Boulder.

In 1987…lightning struck two men who were standing under a tree in downtown Denver. Both were seriously injured and hospitalized.

In 1996…lightning sparked a brush fire in the south buffer zone of the Rocky Flats Environmental Test Facility. No structures were damaged…but the fire burned about 100 acres of grassland before being contained.


In 1892…there was a trace of rainfall each day. This… Together with a trace of rain on both the 7th and 8th…was the only rainfall of the month…making the month the driest on record. The monthly record was equaled in 1944.


In 1901…a thunderstorm produced rain…hail of unknown size… And south winds sustained to 40 mph with gusts to 43 mph.

In 1961…Labor Day snow storm is the earliest date of the first snow…trace and measurable…of the season. The heavy wet snow broke many limbs from trees that were still in full foliage. The storm produced 4.2 inches of snowfall at Stapleton Airport with nearly a foot of snow in western suburbs and in the foothills. Minimum temperature of 33 degrees was a record for the date and the coldest ever recorded so early in the season.

In 1999…severe thunderstorms dumped large hail across metro Denver. Hail as large as 1 inch in diameter was measured near Cherry Creek in Aurora and near Bennett. Hail to 3/4 inch in diameter fell in the city of Denver.

In 2002…a thunderstorm produced a wind gust to 51 mph at Denver International Airport.

In 2003…very heavy thunderstorm rain washed out parts of the Virginia Canyon Road above Idaho Springs. Up to 4 feet of mud reportedly washed down the road during the storm. Several vehicles were trapped on the road. In Idaho Springs…several streets…including the main street… Were also buried in mud and gravel. Some buildings in town experienced minor flooding…including the basement of the town library and the police station.


In 1909…rainfall for the 4 days accumulated to 3.97 inches in Boulder…while in Denver rainfall totaled 2.45 inches on the 4th…5th…and 6th.


In 1909…apparent post-frontal heavy rainfall totaled 1.94 inches in downtown Denver. North winds were sustained to 19 mph.

In 1944…a trace of rain fell. This together with a trace of rain on the 9th…10th…and 30th was the only precipitation for the month. The total of a trace of precipitation for the month equaled the driest September on record first set in 1892.

In 1960…the highest recorded temperature in September…97 degrees…occurred. The same temperature also occurred on September 5…1899…September 1…1995…and September 4… 1995.

In 1989…a strong thunderstorm wind gust flipped a plane taxiing on a private runway in Adams County east of Denver. Two people were slightly injured and the plane was heavily damaged.

In 1992…strong winds developed across metro Denver behind a pacific cold front. Sustained winds above 40 mph with gusts as high as 60 mph were recorded mainly in and near the foothills. Pre-frontal south winds gusted to 37 mph at Stapleton International Airport.

In 1995…two people were injured when lightning struck their home in Lakewood. The lightning entered the attic where it started a small fire. It then traveled through the walls… Exploding a mirror and spraying glass on the residents. Lightning also sparked small grass fires near Aurora…Denver International Airport…and Bennett. The highest recorded temperature in September…97 degrees…occurred. The same temperature also occurred on September 5…1899…September 4…1960…and September 1…1995.

In 2000…thunderstorm winds gusted to 64 mph in Castle Rock.

» Click here to read the rest of September 2 to September 8: This week in Denver weather history

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Thornton’s September weather preview: Typically a very pleasant month for us

Thursday, September 6th, 2018 5:40am MST

Following on an August that saw seasonal temperatures but little precipitation, some are certainly hoping for a bit of the wet stuff in September.  The month can bring plenty of rain and even our first snow of the season but more often than not, it is one of the most pleasant along the Colorado Front Range.

As temperatures start to drop, September usually reminds us that summer is at an end and fall is now here. Sunshine is predominant though as the month actually has the highest percentage of sun out of any month. Sunny days and clear, cool nights are the standard weather pattern for the month.

The month can bring extremes however.  We will of course forever remember 2013’s devastating floods brought on by record-setting rain.  Longtime residents might remember September 1971 which brought over 17 inches of snowfall.

Get a complete look at September’s weather and more details as to what we can expect this year here.

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Thornton’s Thursday brings one more day with cooler than normal temps, potential storms

Thursday, September 6th, 2018 4:58am MST

Today should be the last of our series of days with temps below normal and wet conditions. Things look to dry out and warm up for Friday and the weekend.

For today, there will be some cloud cover throughout with a few breaks in the clouds this morning. Temperatures will be topping out around 77 degrees, about five degrees below normal.

Thunderstorms are again expected to develop this afternoon with a bit better chance for us to see some activity than yesterday. Best opportunity will come from mid-afternoon into the early evening.

Tonight, any showers will be coming to an end relatively early and skies will be partly clear. Overnight lows will be in the mid-50s.

Quickly glancing ahead, drier and warmer air arrives for Friday and is expected to last into next week. Highs tomorrow will be right near normal then the weekend will see readings above normal. Get more details in the extended weather forecast here.

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Cool, damp conditions for Thornton’s Wednesday

Wednesday, September 5th, 2018 5:03am MST

That was a fun little show early this morning, eh? Following our quick drenching and thunder and lightning show, today will see cooler than normal temps and a few lingering, isolated showers.

Cloudy skies start things off and we will see a pretty solid bit of cloud coverage through the morning. This afternoon should bring a little bit of a break.

Shower activity will wind down early this morning leaving only light, isolated activity for most of the daytime hours. This afternoon we may throw in a bit of thunder. Most activity should be in the high country and to our south though. Highs today will top out in the mid-70s.

Tonight, a few, light showers may occur then any activity will end after midnight. Lows will dip to the mid-50s.

Keep an eye on our interactive radar to see where the rain is falling.

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

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

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 MST

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 MST
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 MST

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 MST

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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