Thornton, Colorado, USA
UpdatedTue, 12-Dec-2017 2:25pm MST 


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October 2017 weather recap: Month offers cooler and wetter than normal conditions

Friday, November 3rd, 2017 4:03pm MST

The month of October certainly saw its fair share of varying temperatures.  We seemed to go back and forth between unseasonably warm to unseasonably cold readings.  The month also brought us our first measurable snow of the season and a good bit of precipitation.

The month started with comfortable readings and dry conditions.  On the 9th of the month though things turned considerably colder and Thornton recorded 4.1 inches of snow.

We immediately rebounded though and warmer weather returned.  A string of 70 plus degree days from the 16th to the 20th were quite nice.  We also stayed dry until the last week of the month.

On the 25th we saw a record-setting high temperature but then 72 hours saw our coldest reading of the month (19.4 degrees).  There again, we bounced back with a warm day on the 29th before finishing up with much colder weather the last two days of the month.  We did see some minimal rain on the 26th and 30th to add to the precipitation total for the month.

Thornton saw an overall average monthly temperature of 48.6 degrees.  This was a good ways below Denver’s long term October average of 50.9 degrees.  Out at DIA where the Mile High City’s official measurements are taken, they were warmer with an average of 50.1 degrees.

Our mercury readings ranged from a high of 84.9 degrees on the 25th down to the 19.4 degree reading on the 27th.  DIA saw similar extremes with a maximum of 84 degrees and a minimum of 13 degrees on those same dates.  The reading of 84 degrees on the 25th was a record high for the date.

In terms of precipitation, Thornton recorded 1.71 inches.  Denver lagged considerably with 0.96 inches for the month.  Those put Thornton well above, Denver just below the October average of 1.02 inches.

Denver averages 4.0 inches of snowfall in October.  Thornton bested that by just a bit with 4.6 inches, the majority of which came on the 9th.  Out at the airport, they could only tally 2.8 inches of the white stuff.

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

Thornton, Colorado October 2017 temperature summary. (ThorntonWeather.com)

Thornton, Colorado October 2017 temperature summary. (ThorntonWeather.com)

Thornton, Colorado October 2017 precipitation summary. (ThorntonWeather.com)

Thornton, Colorado October 2017 precipitation summary. (ThorntonWeather.com)

From the National Weather Service:

303 AM MDT WED NOV 1  2017




                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
 HIGH              89   10/16/1991
 LOW               -2   10/29/1917
HIGHEST            84   10/25        83       1       86  10/16
LOWEST             13   10/27        22      -9       25  10/20
AVG. MAXIMUM     64.5              65.3    -0.8     74.5
AVG. MINIMUM     35.7              36.6    -0.9     41.2
MEAN             50.1              50.9    -0.8     57.8
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      0               0.4    -0.4        0
DAYS MIN <= 32     11               8.5     2.5        3
DAYS MIN <= 0       0               0.0     0.0        0

 MAXIMUM         4.17   1969
 MINIMUM            T   1934
TOTALS           0.96              1.02   -0.06     0.26
DAILY AVG.       0.03              0.03    0.00     0.01
DAYS >= .01         5               5.3    -0.3        3
DAYS >= .10         4               2.4     1.6        1
DAYS >= .50         0               0.5    -0.5        0
DAYS >= 1.00        0               0.1    -0.1        0
 24 HR. TOTAL    0.35   10/09 TO 10/09           10/05 TO 10/06

 TOTAL             2.8
TOTALS            2.8               4.0

HEATING TOTAL     455               440      15      231
 SINCE 7/1        585               581       4      310
COOLING TOTAL       1                 5      -4       17
 SINCE 1/1        881               769     112      878

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

AVERAGE WIND SPEED              10.3

AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR           11
NUMBER OF DAYS PC             15


THUNDERSTORM              3     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       1
LIGHT RAIN                8     FREEZING RAIN              1
LT FREEZING RAIN          1     HAIL                       0
HEAVY SNOW                0     SNOW                       4
LIGHT SNOW                4     SLEET                      0
FOG                      10     FOG W/VIS <= 1/4 MILE      5
HAZE                      6

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Thornton’s weekend weather to bring milder temps, some wind

Friday, November 3rd, 2017 5:10am MST

Mother Nature should allow us to warm up a good bit today and tomorrow before returning us to season temps Sunday. The one hiccup along the way will be some breezy winds Saturday.

For today, there is a good bit of moisture and some spots may see some fog early on. After that, look for the clouds to clear and by mid-morning mostly sunny skies will be the rule. Temperatures will warm up to a high in the mid-60s.

Tonight, skies remain mostly clear with lows dipping to 42 degrees.

Saturday will bring even warmer mercury readings but unfortunately with some wind. Mostly sunny skies will be above with downslope winds helping to drive us to highs in the low 70s. The wind will be pretty persistent throughout the day then ease up after dark.

Saturday night into Sunday morning, partly clear skies will be above. Sunday morning lows dip to near the 40 degree mark.

We close out the weekend on Sunday with seasonal temperatures seeing highs in the mid-50s. There will be a decent bit of cloud cover during the day though.

Have a great weekend!

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Thornton’s November 2017 preview: A fall month that can offer up just about anything

Friday, November 3rd, 2017 3:43am MST

Thornton's November weather previewThe weather during the month of November in Denver metro area can offer just about anything.  While it is normally a quiet month, it can be prone to extremes.

November has historically been one of Denver’s snowiest months and major snowstorms are not entirely uncommon.  However conditions can also be quite dry.

Temperatures during the month continue to cool as we get closer to winter and by the end of the month the low temperatures routinely dip to 20 degrees or below.  At times it can in fact bring conditions more like what we see in January.

What lies ahead for November 2017?  Get all the details on November’s weather and what we can expect in our complete preview here.

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Daylight Saving Time to come to an end on Sunday, November 5, 2017

Thursday, November 2nd, 2017 6:00am MST
The United States returns to Standard Time at 2:00am Sunday as Daylight Saving Time comes to an end.

The United States returns to Standard Time at 2:00am Sunday as Daylight Saving Time comes to an end.

The biannual ritual of changing our clocks to adjust for Daylight Saving Time occurs tonight providing yet another signal of the changing of seasons.  The United States will ‘fall back’ one hour at 2:00am Sunday morning as we return to Standard Time.

The ritual of changing our clocks twice a year can be met with some resistance as some people struggle to adjust their body’s internal clock.  Others actually like the return to standard time as they get to enjoy an extra hour of sleep.

The time change definitely has big effects on the dawning of daylight and how early it gets dark in the evening.

Sunrise on Saturday occurs at 7:32am but on Sunday it will be at 6:33am. Similarly, sunset will occur at 5:54pm on Saturday but on Sunday the sun will disappear over the horizon at 4:53pm.

For many this means that when they get home from work it will now be dark and outdoor activities will be significantly curtailed as a result.

Arizona and Hawaii are the only states that do not observe Daylight Saving Time and remain on Standard Time year round.    The U.S. territories of Puerto Rico, American Samoa, Guam, Northern Mariana Islands, and the United States Virgin Islands also do not observe the event.

It won’t be all that long though before Daylight Saving Time returns.  On March 11, 2018 we will ‘spring forward.’

Daylight Saving Time Schedule

The mandated beginning and end of Daylight Saving Time has changed in the United States over the years.

The most recent schedule was set by the Energy Policy Act of 2005 and took effect in 2007.  We now ‘spring forward’ to begin Daylight Saving Time on the second Sunday in March and ‘fall back’ with the return to Standard Time on the first Sunday in November.

Year DST Begins 2 a.m.
(Second Sunday in March)
DST Ends 2 a.m.
(First Sunday in November)
2017 12 March 2017 5 November 2017
2018 11 March 2018 4 November 2018
2019 10 March 2019 3 November 2019
2020 8 March 2020 1 November 2020
2021 14 March 2021 7 November 2021
2022 13 March 2022 6 November 2022
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Thursday to offer warmer than normal temps, less wind

Thursday, November 2nd, 2017 5:24am MST

Today we get a break from all that wind that we saw yesterday. Temperatures will be warmer than normal but with a good bit of cloud cover.

Partly sunny skies start things off and we will see a pretty consistent level of cloud coverage throughout the day. Some sun will peek through occasionally. Temperatures start out chilly and will take a while to start warming up. Once they do, we should be on our way to a high in the low to mid-60s but those clouds may inhibit the highs a bit. Overall conditions will be dry and calm.

Tonight, skies will clear some and lows will dip to around 40 degrees.

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Very mild temps, windy conditions for Wednesday

Wednesday, November 1st, 2017 5:00am MST

If you just looked at the temperature forecast for today you might be pleased. However, while it will be quite warm, we are also going to see a healthy dose of wind that will dampen that enthusiasm.

The day starts with partly sunny skies and overall we should see those same conditions above throughout the day. The wind will be the main focus with speeds in increasing through the morning hours and peaking in the afternoon. Gusts to 45 mph or so will be possible at points. The downslope winds will help us be quite warm today with highs reaching the mid-70s.

This evening the winds should ease quickly and be calm overnight. Low temperatures into tomorrow morning will bottom out around 40 degrees under mostly cloudy skies.

Keep an eye on those windspeeds here.

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Thornton’s Halloween weather to feature clearing skies, warmer temps

Tuesday, October 31st, 2017 4:59am MST

Our latest storm system is on its way out and conditions will improve just in time for the trick-or-treaters. While it will still be cool, it will be much warmer than yesterday and far better conditions for the ghouls and goblins this evening.

The day starts with a good bit of cloud cover but will decrease through the morning leading to mostly sunny skies this afternoon. Winds will be light of the north initially shifting to come out of the east in the afternoon.

Temperatures start out cold and below freezing but then begin a steady climb. Look for our mid-afternoon high to be around 53 degrees – 20 degrees warmer than yesterday but still 6 degrees cooler than normal for the date.

For this evening, we will see clouds increase some after dark but conditions remain calm. Temps at 6:00pm will be in the mid 40s then dip to around 40 by 7:00pm. Definitely a ‘cost under the costume’ night for the little ones.

Tonight, partly cloudy skies will be above and lows drop to the mid-30s.

Live conditions.

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Wintry weather starts off Thornton’s workweek

Monday, October 30th, 2017 5:15am MST

Quite a change in the weather today from what we enjoyed yesterday. Today, the bottom falls out with cold temperatures, freezing drizzle and snow.

The day starts off with a wintry mix of freezing drizzle and some light snow. Similar forms of precipitation can be expected through about 10:00am when things will then begin to taper off. Minimal accumulations are expected, likely less than a half inch if that.

Temperatures will reflect big changes today with temperatures staying right around the freezing mark and our high coming in somewhere around 33 degrees. Roads may be a bit slick in spots given the precipitation and cold temperatures so be careful.

Tonight, skies will clear some and the mercury will dip to the low 20s. Early tomorrow AM there may be a few snowflakes that fall but no accumulation is expected.

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October 29 to November 4: This week in Denver weather history

Sunday, October 29th, 2017 5:17am MST
This Week In Denver Weather History

October 23 to October 29: This Week in Denver Weather History

The further we go into the cold season, the more we see significant winter-like events in our look back at Denver weather history. Many significant snowstorms have occurred this week in the past including one in 1946 that dumped more than 30 inches of snow on Denver.

From the National Weather Service:


In 2009…a powerful early season storm brought heavy snow to the Front Range. The combination of a deep northeasterly upslope flow coupled with abundant moisture and lift with the developing storm system produced an extended period of moderate to heavy snowfall. The heavy wet snow accumulated on trees and resulted in broken branches and scattered electrical outages. Interstates 70 and 76 were closed east of Denver. Numerous other roads and highways were shut down. The Red Cross set up numerous emergency shelters for stranded travelers. The blowing snow at Denver International Airport forced the cancellation of hundreds of flights. Schools were also closed. In the foothills storm totals included: 46 inches… 3 miles southeast of Pinecliffe; 42 inches…3 miles southwest of Conifer; 34 inches…3 miles north of Blackhawk; 30 inches at Aspen Springs and near Evergreen… 23 inches at Roxborough Park…and 20 inches…3 miles south-southeast of Morrison. Across the Urban Corridor storm totals included: 25 inches in Highlands Ranch; 21.5 inches near Louisville…20.5 inches in Broomfield…20 inches at Lafayette…17.5 inches in Boulder…17 inches in Westminster…16.5 inches in Erie; 15.5 inches in Arvada and 5 miles west-northwest of Littleton…15 inches in Littleton…14 inches in Englewood…13.5 inches in Lakewood and 6 miles north of Thornton; 13.3 inches at Denver International Airport…11 inches…4 miles south of Denver; 10.5 inches…2 miles north of Cherry Hills Village and Niwot.


In 1993…an upper level disturbance combined with a moist upslope flow to bring heavy snow to portions of metro Denver. Snowfall amounts ranged from 5.4 inches at Stapleton International Airport to 14 inches in Boulder. New snowfall totaled 8 inches at Gross Reservoir in the foothills 5 miles southwest of Boulder. On the 28th…north winds gusted to 30 mph at Stapleton International Airport where the temperature climbed to only 25 degrees on the 29th…equaling the record low maximum for the date.


In 1971…a vigorous cold front plunged temperatures from a high of 70 degrees on the 27th to record low levels on the 29th and 30th. Snowfall totaled 3.1 inches at Stapleton International Airport where north winds gusted to 23 mph. Some freezing drizzle also fell on the 28th. Record daily low maximum temperatures of 32 degrees on the 28th and 25 degrees on the 29th were established along with a daily record minimum of 13 degrees on the 30th.


In 1929…rain changed to snow on the afternoon of the 28th and continued until midday on the 30th followed by intermittent light snow which continued through the 31st. Snowfall over the four days totaled 16.2 inches in the city. Most of the snow…8.5 inches…fell on the 29th with 6.1 inches on the 30th. Temperatures hovered in 20’s during most of the storm.


In 1917…the all-time lowest recorded temperature in October…2 degrees below zero…occurred. This is also the earliest below zero reading of the season.

In 1939…the first measurable snow of the season totaled 5.6 inches in downtown Denver. Post-frontal northeast winds were sustained to 28 mph.

In 1961…heavy snowfall measured 6.0 inches at Stapleton Airport where northeast winds gusted to 30 mph.

In 1973…strong winds caused some damage to homes…stores… And utility lines along the foothills from metro Denver south.

In 1981…high winds buffeted the Front Range foothills with gusts to 55 mph in south Boulder.

In 1996…high winds gusting from 70 to around 100 mph blasted metro Denver. One man was killed when a strong wind gust overturned a pop-up camper onto him while he was trying to secure it. In addition…five people at the Rocky Flats Environmental Test Facility received minor injuries when several windshields were blown out of their cars…spraying glass onto the occupants. Several trees and power lines were also downed. Two 75-foot high pine trees were uprooted at the Mt. Olivet cemetery in Arvada. Property damage from the windstorm ran into the millions of dollars. The highest recorded wind gusts included: 101 mph at Jefferson County Airport near Broomfield…100 mph in Golden Gate Canyon…96 mph in Coal Creek Canyon…and 87 mph at upper Table Mesa in Boulder. West-northwest winds gusted to 43 mph at Denver International Airport. Insured damage from the wind storm totaled 5.2 million dollars…the third most costly storm of record in Colorado at the time.

In 2003…strong Chinook winds developed in and near the Front Range foothills. Winds gusting to 80 mph in Boulder downed several trees and power lines…causing damage and triggering scattered electrical outages. The combination of strong winds…very dry fuel conditions…and downed power lines sparked two large wildfires. The overland wildfire in Boulder County…near Jamestown…consumed nearly 3900 acres and destroyed 12 structures…including homes…trailers…and out-buildings. Preliminary damage estimates for the value of lost property was nearly one million dollars. In Douglas County…the Cherokee Ranch wildfire consumed 1200 acres and destroyed 4 structures. The large smoke plumes from both fires were highly visible across metro Denver. West winds gusted to 45 mph at Denver International Airport.


In 1905…heavy snowfall developed on the evening of the 29th and continued through the evening of the 30th. Snowfall totaled 11.0 inches in downtown Denver. Precipitation was 1.02 inches. Temperatures were generally in the 20’s.

In 1959…rain during most of the day on the 28th changed to snow early on the 29th and continued through most of the 30th. Heavy snowfall totaled 7.4 inches at Stapleton Airport. North-northeast winds gusted to 24 mph on the 30th. Some freezing drizzle also occurred on the 30th.

In 1981…4 to 8 inches of new snow were recorded in the foothills west of Denver. Snowfall totaled only 0.4 inch at Stapleton International Airport where north winds gusted to 25 mph.


In 1889…the first snowfall of the season totaled 14.0 inches over the three days in downtown Denver. Snowfall was 8.0 inches on the 29th and 5.0 inches on the 31st. North to northeast winds gusted to 30 mph on the 29th.

In 1950…a warm spell resulted in five daily temperature records. Record highs of 84…80…and 79 degrees occurred on the 29th…30th…and 31st…respectively. Low temperature of 49 degrees on the 30th was the record high minimum for the date.

In 1991…the second surge of cold arctic air in a matter of days plunged metro Denver into the deep freeze. While low temperatures remained above zero…high temperatures were only in the 20’s. Three temperature records were set: record lows of 7 degrees on the 30th and 10 degrees on the 31st and a record low maximum of only 21 degrees on the 30th. Snowfall was light with only 1.9 inches recorded at Stapleton International Airport where east winds gusted to 23 mph.

In 2002…snowfall totaled 4.3 inches at the site of the former Stapleton International Airport. North winds gusted to 32 mph on the 29th behind a cold front…which plunged temperatures well below seasonal normals. High temperatures of 18 degrees on the 30th and 19 degrees on the 31st were record low maximums for each date. Low temperatures dipped to 12 degrees on the 30th and 15 degrees on the 31st.


In 1972…heavy snowfall totaled 15.5 inches at Stapleton International Airport. However…the heaviest snow occurred on Halloween night when 7 inches fell on trick-or-treaters during a short 3-hour period. I-25 was closed south of Denver. North winds gusting to 29 mph caused some blowing snow on the 1st. The snow started late on the 29th and ended during the mid afternoon on the 1st. The greatest snow depth on the ground at Stapleton International Airport was 13 inches on the 1st.

» Click here to read the rest of October 29 to November 4: This week in Denver weather history

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Thornton’s Friday and weekend start chilly, will see gradually warmer temperatures

Friday, October 27th, 2017 5:06am MST

The last weekend of October will initially see some lingering effects from yesterday’s storm. However, temperatures will get warmer each day and the three-day period finishes out nicely.

We start out with a very cold Friday morning with mostly clear skies. Temperatures will warm up slowly but remain below normal with highs in the mid-40s. Tonight, there will be a good bit of cloud cover with overnight lows into Saturday morning dipping to just below freezing.

Saturday gets a good bit warmer but also with more cloud cover due to increased moisture aloft. Highs tomorrow will be in the upper 50s. Saturday night will see skies clear and lows drop to the mid to upper 30s.

We close out the weekend on Sunday with the nicest day of the period. Mostly sunny skies will be above and temperatures topping out in the mid to upper 60s.

Our next storm system arrives Sunday night / Monday morning and will see things turn colder and again offer up a chance for some light snow.

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