Category Archives: Thornton Weather

Record high temperature set for December 3rd

Not since Grover Cleveland was president has Denver had as warm of a December 3rd as today.
Not since Grover Cleveland was president has Denver had as warm of a December 3rd as today.Not since Grover Cleveland was president has Denver had as warm of a December 3rd as today.

If you looked at a thermometer late this morning or early this afternoon you might have found yourself wondering if the calendar that says it is December is correct.  Not since 1885 when Grover Cleveland was inaugurated as the 22nd president of the United States and  the Washington Monument was completed has Denver had as warm of temperatures on December 3rd as today. 

At 11:41am this morning the temperature at the official Denver weather station at Denver International Airport reached 69 degrees.  Thornton topped that slightly as we recorded 70.2 degrees at 12:13pm. 

As is often the case, the warmer temperatures have been brought on my strong winds.  Gusts this afternoon to 45mph are possible, particularly along the usual wind-prone areas in the foothills like   Highway 93 between Boulder and Golden.

The warmth will be short-lived however as those winds bring in a cold front later this evening.  Overnight and into tomorrow some areas of the Front Range may see a wintry mix of snow and freezing drizzle.  Highs on Saturday will only reach the mid to upper 30s.  For the complete local Thornton forecast click here.

Related (Examiner.com): Do Denver weather and climate records have an asterisk attached?

ThorntonWeather.com note: Some media outlets, including KMGH Channel 7, are incorrectly reporting that Denver hit a high temperature of 70 degrees today and broke the record.  This is incorrect. 

National Weather Service observations are initially reported in Celsius, rounded to the nearest whole degree – in today’s case, 21 degrees Celsius (70 degrees Fahrenheit).  However the true temperature is recorded to the nearest tenth of a degree.  Today’s actual high temperature was 20.6 degrees Celsius or 69 degrees Fahrenheit. 

Yet another reason to rely on ThorntonWeather.com for your weather news and information!  😉

Colorado mountains set to be slammed by major snowstorm

A major winter storm will bring heavy snow to much of western Colorado.
A major winter storm will bring heavy snow to much of western Colorado. (NWS)

As travelers prepare to hit the road to visit friends and family for the Thanksgiving holiday, a major winter storm set to strike the Western Slope may cause problems.  Some areas will be measuring snow in terms of feet rather than the usual inches. 

A strong Pacific trough of low pressure will begin encroaching on western Colorado today followed by a cold front on Sunday.  These factors will combine to bring heavy snow to much of the western third of the state where Winter Storm Warnings have been posted.

The long-lasting storm will bring periods of heavy snow lasting from today through Wednesday.  The San Juans will bear the brunt through tomorrow followed by the Sawatch and Elk mountain ranges from Monday through Wednesday.  Areas farther north along the Rockies will also feel the effects. 

Here in Thornton and the Denver metro area things will be much calmer but also cooler, particularly on Wednesday and Thanksgiving Day.  High temperatures for those two days may not even reach the freezing mark.  At the current time it does appear we will remain dry so flying into and out of Denver International Airport (DIA) should not be a problem. 

Get the rest of the story on Examiner.com.Get more details including a look at current weather warnings for Colorado on the Denver Weather Examiner.

Denver’s October 2010 wraps up dry and warm

October 2010 ended up drier and warmer than normal.
October 2010 ended up drier and warmer than normal.

Following on what was a “top 10” warmest and driest September, October tried to follow suit but fell short of achieving record status.  Nevertheless, the month was considerably warmer and drier than normal. 

In terms of temperature the month ranked as the 11th warmest fall just 0.1 degree short of top 10 status.  The average temperature was 55.3 degrees; a considerable 4.3 degrees above normal.  Temperatures ranged from a high of 85 degrees on the 3rd down to a low of 20 on the 28th.  In all there were only two days when the mercury dipped to freezing or below; seven days below the normal nine we receive. 

Thornton was quite a bit cooler overall than Denver as we had an average temperature of 52.7 degrees.  Highs ranged from 84 degrees on the 4th down to 23.3 degrees on the 28th. 

As an interesting side note, it was just last October that we had our second coldest October on record.  The average temperature in October 2009 was a chilly 42.9 degrees and we had 17 days with temperatures at or below freezing! 

We suffered through another dry month which did spark a couple of wildfires.  A mere 0.54 inch of precipitation was recorded at the official monitoring site at Denver International Airport.  This was just barely more than half of the normal of 0.99 inch.  Most of the precipitation fell in the form of rain on the 12th when 0.34 inch was recorded.  Here in Thornton we were a bit wetter having recorded 0.73 inch of precipitation during the month. 

For the first time since 2003 no snow was recorded in Denver in October.  This is only the 15th time since 1882 that has happened.  On average we expect to receive 4.1 inches of the white stuff. 

See the official statistical summary from the National Weather Service below for more details.  Click here to view the monthly climate summary for Thornton.

CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
205 PM MDT MON NOV 1 2010

................................... 

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF OCTOBER 2010...

CLIMATE NORMAL PERIOD 1971 TO 2000
CLIMATE RECORD PERIOD 1872 TO 2010

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR'S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              90   10/01/1892
 LOW               -2   10/29/1917
HIGHEST            85   10/03        90      -5       84  10/18
LOWEST             20   10/28        -2      22       17  10/10
AVG. MAXIMUM     69.7              66.0     3.7     54.7
AVG. MINIMUM     40.9              35.9     5.0     31.1
MEAN             55.3              51.0     4.3     42.9
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      0               0.3    -0.3        3
DAYS MIN <= 32      2               8.6    -6.6       17
DAYS MIN <= 0       0               0.0     0.0        0
PRECIPITATION (INCHES) 
RECORD
  MAXIMUM         4.17   1969  
  MINIMUM            T   1934
TOTALS           0.54              0.99   -0.45     1.36
DAILY AVG.       0.02              0.03   -0.01     0.04
DAYS >= .01         4               5.3    -1.3        8
DAYS >= .10         2                MM      MM        5
DAYS >= .50         0                MM      MM        0
DAYS >= 1.00        0                MM      MM        0
GREATEST
 24 HR. TOTAL    0.34   10/12 TO 10/12     0.39  10/20 TO 10/21       

SNOWFALL (INCHES)
RECORDS
 TOTAL           31.2   1969
TOTALS            0.0               4.1    -4.1       17.2             

DEGREE_DAYS
HEATING TOTAL     300               436    -136      676
 SINCE 7/1        335               582    -247      815
COOLING TOTAL       8                 0       8        0
 SINCE 1/1        870               696     174      533              

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
.................................................................

WIND (MPH)
AVERAGE WIND SPEED              9.1               9.6
RESULTANT WIND SPEED/DIRECTION   3/231            MM
HIGHEST WIND SPEED/DIRECTION    41/350  10/25    37/350  10/29/09
HIGHEST GUST SPEED/DIRECTION    51/350  10/25    54/200  10/05/09

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM                                      

NUMBER OF DAYS FAIR            9
NUMBER OF DAYS PC             22
NUMBER OF DAYS CLOUDY          0

AVERAGE RH (PERCENT)     44

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              4     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       3
LIGHT RAIN                5     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                0     SNOW                       0
LIGHT SNOW                0     SLEET                      0
FOG                       2     FOG W/VIS <= 1/4 MILE      1
HAZE                      7                                           

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

Denver’s frightening Halloween weather

Many long-time Denver residents believe it always snows on Halloween. Is it fact or fiction?

As a kid growing up in Denver it always seemed like Mother Nature put a damper on our trick-or-treating.  Conventional wisdom in the Denver area is that it always seems to rain or snow on Halloween.  

But, is there any truth to this urban legend?  Or is this just one of those times where our memory doesn’t serve us quite right? 

This year it looks like we have nothing to worry about but  the National Weather Service has been kind enough to compile weather statistics just for Halloween.  As it turns out, the thought of snow and rain on Octboer 31st isn’t just in our minds! 

Get all the details in our Denver Halloween statistics and info page!  Click here!

Will it snow this Halloween?  Get the latest forecast here.

The first full month of fall arrives; What will October weather bring to Thornton?

October is here and it may bring Denver's first taste of snow and freezing temperatures for the season.
October is here and it may bring Denver's first taste of snow and freezing temperatures for the season. (iStockphoto / johnnyscriv)

With the first full month of fall here, October usually brings one of the quietest weather months in the Denver area with plenty of mild, sunny days and clear, cool nights.  Certainly given our recent trend of well-above normal temperatures many are hoping for some relief. 

The month actually has our second highest amount of sunshine with 72 percent with September having the most with 74 percent. Interestingly enough, the month following, November, is one of the lowest sunshine months with only 64 percent.

Typically October brings our first real taste of winter with the first freeze on average coming on the 7th of the month and the first snow on the 15th of the month.

You can get all the details including a look back at historical October weather and a look ahead at what October 2010 is expected to bring in our complete preview here.

Mother Nature keeps the heat on – Another record high temperature set

For the fourth time this month Denver set (or tied) a record high temperature.
For the fourth time this month Denver set (or tied) a record high temperature.

Mother Nature obviously hasn’t gotten the message that it is now September and fall is here.  Once again Denver broke a record high temperature – the fourth time we have tied or broken a record this month. 

According to the National Weather Service the temperature at Denver International Airport reached 92 degrees at 3:55pm.  This shatters the old record high for the date of 89 degrees that was set twice, once in 1994 and before than in 1892.

Here in Thornton we were a couple of degrees cooler as we reached a high of 89.7 degrees at 2:41pm.

This is the fourth time this month that we have tied or set a new record high temperature and September 2010 may very well end up as one of the top 10 warmest on record. 

As of midnight the average temperature in Denver during September had been 67.0 degrees.  If the month were to have ended then we would be in a tie with 1939 for the 7th warmest September on record (see list below). 

With temperatures forecast to remain in the mid-80s on Wednesday and around 80 on Thursday it is very possible September 2010 will fit on that top 10 list somewhere.  We are certain to far exceed the average September temperature of 62.4 degrees. 

DENVER’S 10 WARMEST SEPTEMBERS
(1873-2009)

 68.3   1948
 68.2   1931, 1981
 68.0   1998 (cor)
 67.7   1933
 67.6   1947
 67.2   1994, 2005
 67.0   1939
 66.9   1990
 66.8   2001
 66.6   1977
 

Another record-setting Sunday as Denver ties all time high temperature for September 26

For the second Sunday in a row the mercury in Denver reached a record-setting mark.
For the second Sunday in a row the mercury in Denver reached a record-setting mark.

The Mile High City is on pace to see one of its “top 10 warmest” Septembers on record and that was in full evidence on Sunday.  For the third time this month we have tied or broken a record high temperature. 

At Denver International Airport today the high temperature reached 90 degrees at 2:54pm thus tying the record for the date set in 1892.  This is far above the normal high temperature of 74 degrees for the date. 
Here in Thornton we were slightly cooler as we recorded a high temperature of 88.1 degrees at 3:07pm today. 
 
Denver also broke a high temperature record on Monday, September 20th when the mercury climbed to 94 degrees. This bested the old record for the date of 92 degrees set in 1956.
 
Last Sunday, September 19th, the mercury topped out an amazing 96 degrees. That broke the old record of 93 degrees set in 1980. It was also the hottest temperature ever recorded so late in the year and was the hottest Denver Broncos home game on record. 
 The recent wildfires have reminded us just how dry Denver has been in recent weeks and the precipitation measurements bear this out. Thus far this month Denver has recorded a mere 0.06 inch of precipitation – far below the average for September of 1.14 inches.
 
Given that at the current time there is no moisture in the weather forecast through the end of the month, September 2010 may very well go into the record books as one of the top 10 driest Septembers on record. If the month were to end today it would tie for 5th place on the list with 1882 and 1920.
 
In terms of temperature the month also is threatening top 10 status. As of yesterday the average temperature for the month has been 66.8 degrees. That is more than four degrees above the normal of 62.4 degrees. If the month were to end today that would put the month in a tie for the 9th spot on the top 10 warmest Denver Septembers on record.  

Ready for snow and freezing temperatures? They can come at any time now

Are you ready? As September comes to a close and with fall's arrival cold and snow aren't far behind usually.

Wednesday marked the first day of fall and while the forecast may not call for freezing temperatures or snow, it won’t be long before the Mile High City is faced with those conditions.  We have in fact already passed the earliest dates Denver has seen freezes and snow so they can arrive at any time. 

Denver has in fact seen snow as early as September 3rd and its first seasonal freeze as early as September 8th.  Those are the extremes however.  On average the first snowfall occurs on October 19th and the first freeze on October 7th.

How will we fare this year?  La Niña conditions are strengthening and the outlook is for warmer than normal temperatures for the next few months.  Colorado weather however doesn’t always follow an established pattern. 

Below is a look at Colorado’s cold season statistics as provided by the National Weather Service.  They provide a bit of historical perspective as to what we might expect this year.

  • The statistics below and many more are kept in our Climatology section. Check it out

Autumn First Freeze Information

Earliest Date of First Freeze: September 8, 1962
Latest Date of First Freeze: November 15, 1944
Average Date of First Freeze: October 7th
 
First Freeze Last 11 Years:
October 2, 2009
October 13, 2008
October 8, 2007
September 18, 2006
October 5, 2005
October 14, 2004
September 14, 2003
October 4, 2002
October 5, 2001
September 20, 2000
September 28, 1999
 
October 21st is the average date in which Denver’s normal overnight low temperature hits 32 degrees Fahrenheit for the first time.
 
Autumn First Snow Information
 
Earliest Date of First Snow: September 3, 1961
Latest Date of First Snow: November 21, 1934
Average Date of First Snow: October 19th
 
First Measurable Snow Last 11 Years:
October 21, 2009
November 14, 2008
October 22, 2007
October 18, 2006
October 10, 2005
November 1, 2004
November 5, 2003
October 25, 2002
October 5, 2001
September 23, 2000
September 28, 1999
 
Seasonal Snowfall Amounts

Greatest Seasonal Snowfall: 118.7 inches 1908-09
Least Seasonal Snowfall: 20.8 inches 1888-89
Average Seasonal Snowfall (1971-2000): 61.7 inches
 
Seasonal Snowfall Last 11 Years:
60.6 inches 2009-2010
38.1 inches 2008-2009
46.3 inches 2007-2008
72.6 inches 2006-2007
30.4 inches 2005-2006
39.3 inches 2004-2005
38.0 inches 2003-2004
61.8 inches 2002-2003
30.2 inches 2001-2002
58.3 inches 2000-2001
45.6 inches 1999-2000
 
Denver’s Snowstorm Total Snowfall Statistics
 
Greatest Snowfall From One Storm: 45.7 inches December 1-6, 1913 (recorded between December 4-5th 1913)
 
The Top 13 Denver Snowstorms since 1946:
31.8 inches Mar 18, 2003
30.4 inches Nov 3, 1946
23.8 inches Dec 24, 1982
21.9 inches Oct 25, 1997
21.5 inches Nov 27, 1983
21.2 inches Nov 19, 1991
20.7 inches Dec 20, 2006
18.7 inches Mar 5, 1983
17.7 inches Nov 19, 1979
17.3 inches Apr 1, 1957
16.9 inches Mar 20, 1952
16.0 inches Oct 3, 1969
15.8 inches Apr 26, 1972

Another record smashed – Denver breaks 54 year old high temperature record

For the second day in a row Denver set a high temperature record.
For the second day in a row Denver set a high temperature record.

A sizzling end to summer in the Mile High City!  Following on Sunday’s record setting heat we followed suit again on Monday breaking another high temperature record.

The official high temperature as measured at Denver International Airport reached 94 degrees Monday afternoon at 1:38pm.  This breaks the old high temperature record for the date of 92 degrees set in 1956. 

Here is Thornton we just a slight bit cooler than the official high temperature as ThorntonWeather.com recorded 92.3 degrees as our high temperature. 

The mercury would likely have climbed higher today were it not for some afternoon cloud cover. 

Yesterday Denver reached a high of 96 degrees easily eclipsing the old record for September 19th of 93 set in 1980.  The day also went down in history as the hottest home game temperature in history for the Denver Broncos and the highest temperature ever recorded in Denver this late in the year. 

Tomorrow is the last day of summer but we won’t be breaking any records.  Temperatures will become more seasonal finally as cooler air moves in from the northern plains. 

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Denver smashes record high temperature as 96 degrees hits the Mile High City

Denver recorded a high temperature today of 96 degrees shattering the old record high for the date of 93.
Denver recorded a high temperature today of 96 degrees shattering the old record high for the date of 93.

Denver is closing out summer in sizzling fashion.  With only three days left in summer the Mile High City shattered the record high temperature for the date and may set another one on Monday.

Today at 2:32pm the temperature at Denver International Airport reached a scorching 96 degrees.  This smashes the old record of 93 degrees set 30 years ago in 1980. 

The 96 degree mark today is also the highest temperature ever recorded in Denver this late in the year.  Previously 96 degrees was recorded on September 13, 1990 and in previous years.

Mercifully here in Thornton we weren’t quite as warm.  We recorded a high of 93.6 degrees at 3:20pm.

The temperature today was not a record high for the month of September however.  That mark would be 97 degrees set on the 1st of the month in 1995, the 4th in 1995 and the 5th in 1899. 

More heat is on tap for tomorrow as Denver will approach the 90 degree mark.  The record high for September 20th is  92 degrees set in 1956.

Along with the heat and lack of humidity also comes fire danger.  A Red Flag Warming will go into effect on Monday from noon until 9:00pm.  We have seen how dangerously dry the weather has been with the Fourmile Canyon Fire and the Reservoir Road Fire in the last few weeks.  Please be careful.

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