Thornton, Colorado, USA
UpdatedThu, 22-Feb-2018 12:05am MST 


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December 2017 recap: Despite cold finish, month was warmer and drier than average

Thursday, January 4th, 2018 9:16am MST

With the last part of December fresh in our minds, it would not be surprising to think of the month as a cold one. However, reaching back, if you recall, we actually enjoyed a lot of mild days earlier and very little precipitation. As a result, December 2017 goes into the books as a warm and dry one.

The first half of the month was notable for stable conditions yielding above normal temperatures and no precipitation. Denver set a record high temperature on the 12th of 69 degrees which was also our warmest reading of the month.

Not long after the warmth came the cold.  Arctic air infiltrated from the north on the 21st resulting in much cooler temperatures and a pre-Christmas snow. This was followed by another snow on the 23rd that lasted into the early morning hours of Christmas Eve. Single digit lows were seen for seven days from the 21st to the 27th.

We then saw a brief warmup for the 27th to the 29th but that was short lived. We closed out the month with the final two days’ high temperatures failing to reach even the freezing mark.

On average, Denver’s temperature for December comes in at 30.0 degrees.  Both Thornton and the Mile High City came in above that with average readings of 31.8 degrees and 33.2 degrees respectively.

Thornton saw its warmest temperature reading of 69.1 degrees on the 12th and its coldest of 1.6 degrees on the morning of the 27th.  Denver’s warmest reading of 69 degrees also came on the 12th and its coldest of -4 degrees came on the 24th.

In terms of precipitation, Thornton saw a mere 0.16 inch of liquid in its bucket for the month. Denver was a bit better with 0.21 inches. Both were below the long-term Denver average of 0.35 inches.

December on average brings 8.5 inches of snowfall to Denver.  Thornton fell well short of that with 4.7 inches and Denver just a bit less with 4.0 inches.

Click here to view Thornton’s December 2017 climate report.

Thornton, Colorado's December 2017 temperature summary. (ThorntonWeather.com)

Thornton, Colorado’s December 2017 temperature summary. (ThorntonWeather.com)

Thornton, Colorado's December 2017 precipitation summary. (ThorntonWeather.com)

Thornton, Colorado’s December 2017 precipitation summary. (ThorntonWeather.com)

645 AM MST MON JAN 1 2018




                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
 HIGH              79   12/05/1939
 LOW              -25   12/22/1990
HIGHEST            69   12/12        62       7       65  12/30
LOWEST             -4   12/24        -4       0      -15  12/17
AVG. MAXIMUM     48.3              42.8     5.5     42.7
AVG. MINIMUM     18.0              17.1     0.9     12.9
MEAN             33.2              30.0     3.2     27.8
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      4               5.8    -1.8        6
DAYS MIN <= 32     28              29.4    -1.4       30
DAYS MIN <= 0       1               2.0    -1.0        4

 MAXIMUM         5.21   1913
 MINIMUM         0.00   1881
TOTALS           0.21              0.35   -0.14     0.78
DAILY AVG.       0.01              0.01    0.00     0.03
DAYS >= .01         4               4.1    -0.1        6
DAYS >= .10         1               1.1    -0.1        2
DAYS >= .50         0               0.1    -0.1        0
DAYS >= 1.00        0               0.0     0.0        0
 24 HR. TOTAL    0.10   12/23 TO 12/23
 STORM TOTAL     0.10   12/23 TO 12/23

 TOTAL           57.4   1913
TOTALS            4.0   2017        8.5

HEATING TOTAL     979              1086    -107     1146
 SINCE 7/1       2150              2468    -318     2042
COOLING TOTAL       0                 0       0        0
 SINCE 1/1        881               769     112      878

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

AVERAGE WIND SPEED              10.0

AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR            8
NUMBER OF DAYS PC             18

AVERAGE RH (PERCENT)          49

FOG OR MIST                   12
FOG VSBY LESS 1/4 MI           4
THUNDER                        0
ICE PELLETS                    0
HAIL                           0
DUST STORM                     0
SMOKE OR HAZE                  5
BLOWING SNOW                   0
TORNADO                        0

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Thornton’s Thursday weather to bring unseasonably warm temps, lots of sun

Thursday, January 4th, 2018 4:57am MST

A very pleasant winter day ahead for us. Look for plenty of sun and temps about 10 degrees above normal.

The day starts with a bit of cloud cover but that will quickly dissipate bringing sunny skies by mid-morning. Winds will be light and out of the south, conditions dry. Temperatures will climb nicely and top out in the low 50s.

Tonight, mostly clear skies will be above will lows dipping to the low to mid-20s.

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Wednesday to offer calm conditions, temperatures above normal

Wednesday, January 3rd, 2018 5:01am MST

We promised a warm up and here it comes. Today, we’ll see our first above-average high temperature readings in almost a week.

The day starts with clear skies then we will see a few high clouds in the afternoon but nothing that is intrusive. Winds will be light, conditions calm. Temperatures start out cold as you would expect then will warm up toward a high right near the 50 degree mark. Average for today’s date is 43 degrees.

Tonight, look for partly cloudy skies above and lows near 20 degrees.

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Thornton’s workweek starts with seasonal temps, begins warming trend

Tuesday, January 2nd, 2018 5:06am MST

We finally begin to break out of the chill of recent days with a day on par with normal for today’s date. Looking ahead, we will continue to warm up through the end of the week.

For today, sunny skies will be the rule throughout the daytime hours. Winds will be light and out of the southwest. We start out quite cold but once the sun comes up the mercury will begin a rise with highs today right close to the average of 43 degrees for the date.

Tonight, skies remain clear with lows dipping into the teens.

For the balance of the week, look for temperatures to continue to warm with conditions remaining dry and calm. Right now it looks our next storm system doesn’t arrive until Saturday night and Sunday. The extended weather forecast can be found here.

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Thornton’s January 2018 preview: Cold but not always snow for first month of the year

Monday, January 1st, 2018 6:03am MST

Denver's January weather and climatology preview for 2013.As we begin the new year the winter chill begins to set in.  While January can see its share of extremes, the month historically sees stable temperatures and is usually relatively dry.

January ranks as the second coldest month in Denver next to December with average temperatures remaining virtually the same from the start to the end of the month.

In terms of snowfall, the month only ranks as the fourth snowiest and it is not uncommon for it to be quite dry.

What does January 2018 hold for us?  Follow the link to find out.

For the complete January preview including a look at historical averages and extremes, click here. 

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New Year’s Day to offer chilly temps, dry and calm conditions

Monday, January 1st, 2018 5:13am MST

The first day of 2018 will bring little weather drama to Thornton. Temperatures today will remain on the cold side but otherwise, it will be a quiet one.

Look for a good bit of cloud cover throughout the day today. Those clouds will help to keep temperatures down as we expect a high of only 27 degrees. Winds will be light and out of the northeast, conditions dry.

Tonight, we may see a few snow flurries overnight into tomorrow morning. No accumulation is expected though. Overnight lows will be close to 10 degrees.

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December 31 to January 6: This week in Denver weather history

Sunday, December 31st, 2017 2:21pm MST
This Week In Denver Weather History

December 31 to January 6: This week in Denver weather history

One of our coldest and driest months, January is not normally known for its weather extremes. However just like any in Colorado, significant events can occur as we see in our look back at this week in Denver weather history.

From the National Weather Service:


In 1980…temperatures were unusually warm during the week between Christmas and New Year’s. High temperatures for the week ranged from the mid-50’s to the mid-70’s. Four temperature records were set. Record highs occurred on the 26th with 68 degrees…the 27th with 75 degrees…and the 30th with 71 degrees. A record high minimum temperature of 41 degrees occurred on the 27th.


In 1886…heavy snow totaled 6.5 inches in downtown Denver. Most of the snow…4.5 inches…fell on the 31st. North winds were sustained to 18 mph.

In 1928…snowfall of 0.6 inch was the only measurable snow of the month in the city.

In 1947…post-frontal heavy snow totaled 6.3 inches over downtown Denver. Most of the snow fell on the 30th. North winds were sustained to 17 mph on the 30th.

In 1995…the foothills west of Denver received 5 to 9 inches of new snow…except for Bailey where 11 inches of snow were measured. No snow fell at the site of the former Stapleton International Airport.


In 1890…northeast winds were sustained to 46 mph with gusts as high as 60 mph behind an apparent cold front. A trace of sleet fell.

In 1899…northwest winds were sustained to 44 mph with gusts as high as 48 mph. The Chinook winds warmed the temperature to a high of 49 degrees.

In 1927…the temperature was below zero all day. The high temperature of 3 degrees below zero was a record low maximum for the date. The low temperature was 11 degrees below zero.

In 1970…warm Chinook winds whistled through Boulder. A wind gust to 92 mph was recorded at the National Center for Atmospheric Research…while at the National Bureau of Standards…winds peaked to 70 mph. Northwest winds gusting to 30 mph warmed the temperature to a high of 60 degrees at Stapleton International Airport.

In 1993…occasional high winds occurred northwest of Denver and in the foothills. A wind gust to 85 mph was recorded at Jefferson County Airport in Broomfield. Wind gusts to 86 mph occurred on Squaw Mountain with 75 mph recorded at Rollinsville. West winds gusted to 46 mph at Stapleton International Airport.

In 2011…an intense and fast moving storm system… produced a powerful windstorm across the Front Range. In the mountains and foothills…several locations recorded wind gusts in excess of 100 mph. Numerous trees were knocked down throughout Arapahoe National Forest. One man was killed when he was impaled by a falling tree limb while driving along U.S. Highway 36…north of Boulder. The strong winds produced extensive damage to fences and roofs… and also knocked down trees which resulted in power outages that affected 19 thousand residents along the Front Range.  In the mountains and foothills…peak wind gusts included: 111 mph…3 miles south-southeast of Pinecliffe; 101 mph…1 mile west of Lyons; 94 mph atop Berthoud Pass; 86 mph…3 miles south of Golden; 84 mph… 4 miles northwest of Boulder; 81 mph in Boulder; 79 mph at Kenosha Pass…NCAR Mesa Lab and the junction of U.S. Highways 72 and 93; 77 mph at the National Wind Technology Center; and 76 mph…3 miles north-northwest of Morrison. Peak wind gusts for the Urban Corridor included: 80 mph…3 mile east of Cedar Point; 77 mph in north Longmont; 67 mph…10 miles east of Parker; 64 mph at Buckley AFB and Lakewood; 60 mph at Bennett and Front Range Airport in Watkins; 59 mph at Denver International Airport and Deer Trail; 58 mph at Rocky Mountain Regional Airport in Broomfield and 2 miles north-northwest of Louisville.


In 1900…low temperatures dipped to 19 degrees below zero on both days to establish daily record minimum temperatures.

In 1975…only 4.2 inches of snow fell at Stapleton International Airport…while north of Denver a major blizzard raged. All roads north of Denver into Wyoming were closed when strong winds whipped snow into 5 to 6 foot drifts. North winds gusted to 43 mph at Stapleton International Airport on the 31st…causing some blowing snow. Freezing drizzle also fell on the 31st.

In 1984…heavy snow fell in the foothills with 8 inches at Boulder and 6 inches in southern and western metro Denver. Only 1.5 inches of snow fell overnight at Stapleton International Airport.

In 1991…a New Year’s Eve snow storm dumped 2 to 8 inches of snow across northeastern Colorado. Snowfall totaled 3.4 inches at Stapleton International Airport. The 1.9 inches of snow that fell on the 31st was the only measurable snowfall of the month.

In 2008…another brief period of high winds occurred in and near the foothills of Boulder and Jefferson counties. In Nederland…the strong wind snapped a blue spruce which landed on a nearby propane tank. Some roofs in the immediate area were damaged and power lines were downed; which left 126 residences without electricity for six hours. Peak wind gusts included 90 mph at the national wind technology center…and 89 mph; 6 miles northwest of Boulder. At Denver International Airport…a peak wind gust of 23 mph was measured from the southwest.


In 1973…the 31st marked the start of a protracted cold spell that extended into January of 1974 when temperatures dipped below zero on 7 consecutive days. Record daily minimum readings occurred on the 3rd and 5th when the temperature plunged to 17 degrees below zero on both days. A record low daily maximum temperature of only 4 degrees occurred on the 5th.


In 1941…a protracted cold spell through January 7…1942… Produced below zero low temperatures on 7 of the 8 days. A low temperature of 2 degrees on the 3rd prevented a string of 8 days below zero. The coldest days during the period were the 1st with a high of 2 degrees and a low of 9 degrees below zero…the 4th with a high of 2 degrees and a low of 11 degrees below zero…and the 5th with a high of 26 degrees and a low of 12 degrees below zero.


In 1875…the temperature fell 27 degrees between 3:00 pm and 5:00 pm. The high for the day was 43 degrees…and the low was 8 degrees. Occasional snow flurries fell during the day…but not enough to cover the ground.

In 1885…dense smoke choked the skies over downtown Denver until midday.

In 1910…a rare trace of light rain fell during the morning.

In 1911…post-frontal northeast winds were sustained to 40 mph. Only a trace of snow fell in downtown Denver.

In 1952…snowfall of 0.03 inch was the only measurable snowfall of the month and resulted in 0.01 inch of melted snow…the only precipitation of the month.

In 1956…west-northwest winds gusted to 52 mph at Stapleton Airport.

In 1996…the first snow storm of the new year dumped more than a foot of snow in the Front Range foothills with 4 to 9 inches across the western and southern sections of metro Denver. Snow totals included: 14 inches at conifer; 11 inches at Evergreen; and 10 inches at Eldora Ski Resort… West of Boulder. Snowfall totaled only 1.2 inches at the site of the former Stapleton International Airport. North- northeast winds gusted to 30 mph at Denver International Airport.

In 2003…only a trace of snow fell at the site of the former Stapleton International Airport. This…along with a trace of snow on the 22nd…was the only snow of the month…which equaled the 1934 record for the least snowiest January.


In 1896…warm Chinook winds on the 1st became cold bora winds on the 2nd. Southwest winds sustained to 60 mph with gusts as high as 66 mph warmed the temperature to a high of 55 degrees on the 1st. Northwest winds sustained to 54 mph with gusts to 60 mph resulted in snowfall of 0.3 inch and a high temperature of only 31 degrees on the 2nd.


In 1940…the first days of the month were characterized by a mixture of drizzle…light snow…and fog. Fog occurred on each day. On the 4th and 5th considerable glazing resulted from freezing drizzle. All objects were coated with a glaze on the windward side. This resulted in very slippery streets…which caused several minor traffic accidents. The glaze was not heavy enough to damage wires and cables.

» Click here to read the rest of December 31 to January 6: This week in Denver weather history

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December 2017 top shots: Monthly photo slideshow

Saturday, December 30th, 2017 4:54am MST
Fire in the sky at sunrise on December 3, 2017. (Ed Dalton)

Fire in the sky at sunrise on December 3, 2017. (Ed Dalton)

The month of December can offer everything from bone dry conditions to bone chilling cold and monstrous snowstorms.  The weather and wildlife all afford an abundance of photo opportunities as our December photo slideshow shows.

Leaves have fallen from trees now and the landscape can sometimes look quite stark.  However it only takes a quick shot of snow to change that picture greatly.  Throw in gorgeous sunrises and sunsets, plenty of wildlife big and small, kids playing and much more and the month can be quite colorful and eventful.

  • Slideshow updated December 30, 2017
  • 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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Thornton’s weekend starts warm and breezy, will end quite chilly

Friday, December 29th, 2017 5:53am MST

Downslope winds will drive the temperatures up today and Saturday will be seasonal. A cold front then moves in that will introduce slight chance for snow and much colder temperatures as we ring in the new year.

For Friday, warm, downslope winds drove early morning temperatures up in the pre-dawn hours. Look for those winds and the mild temperatures to last through much of the day.

Tonight, clouds increase and cold air filters in sending the mercury into the teens.

Tomorrow will be a pretty typical day for this time of year. Mostly sunny skies will be above with highs in the mid-40s.

Saturday night into Sunday morning, moisture increases leading to slight chances for some snow although right now it isn’t looking like it will amount to much.

Most notable will be the colder temperatures set for New Year’s Eve and New Year’s Day. High temperatures on both days will be only in the 20s.

Have a great weekend and please stay safe as you ring in the new year.

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Thursday offers up plenty of sun, unseasonably warm temperatures

Thursday, December 28th, 2017 5:15am MST

Thornton will enjoy another very pleasant winter day and that snow on the ground is not long for this world. Look for lots of sun, temps a good bit above normal today.

We start out with clear skies, only a few clouds, and will see that continue through the day. Winds will be light, initially out of the southwest, switching to come out of the north this afternoon.

Temperatures will see a steady climb with today’s high expected to reach right near the 50 degree mark. Average for the date is 43 degrees.

Tonight, skies will be partly clear with lows dipping to the mid-20s. We will see some breezy winds after midnight into tomorrow morning.

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