Category Archives: Climatology

March preview: Snowiest month also typically brings much warmer temperatures

The month of February was quite generous in terms of snowfall pushing our seasonal total thus far above normal.  The month of March usually offers healthy snowfall giving us an opportunity to add to those numbers.  While there is good snow potential in March, the month also typically brings much warmer temperatures.

March is historically Denver’s snowiest month and brings about 20% of our annual snowfall.  Heavy, wet spring snow storms can oftentimes bring the entire month’s snowfall total in one monstrous snow.

We also start the transition to spring and severe weather season and the month typically brings our first thunderstorms of the year.  Temperatures climb throughout the month and by the end our average daytime highs are near 60 degrees.

For a complete look at what lies ahead in March 2014, click here.

February 2015 weather recap: Temps above normal, record-setting snowfall

The month of February was quite an interesting one in terms of its weather.  Overall temperatures for the first half of the month were well above normal but the latter half saw the bottom fall out and as it did, significant snowfall accumulated.

The first day of February brought a healthy shot of snowfall and cold temperatures.  From there, things dried out and warmed up considerably.  Thirteen consecutive days were then seen with above normal mercury readings.  Only one of those thirteen saw precipitation in the form of a light snow on the 4th of the month.

From the 15th through the end of the month, the mercury plunged and only two temperature readings were at or above normal – all the rest were below, some significantly so.  Additionally, Thornton saw 8 days in the last two weeks of the month with measureable snowfall.  Out at the airport, Denver saw similarly snowy conditions and set a record for snowfall during the month of February.

Despite the cold close to the month, overall the month of February saw warmer than average temperatures.  Thornton’s month averaged 34.3 degrees, just a bit above the long term Denver average for the month of 32.5.  The Mile High City was warmer than normal as well with an average reading of 33.8 degrees for the month.

Temperatures in Thornton ranged from a spring-like high of 75.9 degrees on the 7th of the month down to a low of 0 degrees on the morning of the 27th.  Denver’s warmest and coldest readings came on those same dates with 74 degrees and -6 degrees.

Denver set or tied four temperature records for the month.  On February 6th a maximum reading of 70 degrees was a record for the date.  That same day a low temperature of 46 degrees set a record high minimum for the date.  The next day, the 7th, a record high of 74 degrees was set as was a record high minimum of 41 degrees.

In terms of precipitation, the month was quite generous.  On average Denver receives 0.37 inch of liquid precipitation during February.  Thornton saw 1.81 inches while Denver tallied 1.25 inches.

Snowfall was a big part of the month’s story.  We did not receive any large storms but rather prolonged ones that delivered steady, healthy doses.  Thornton totaled 26.7 inches during the month.  Out at Denver International Airport, they lagged the totals in the rest of the metro area with a reading of 22.4 inches.

Denver’s reading of 22.4 inches, while lower than ours, allowed February 2015 to go into the weather history books as the snowiest February on record in the Mile High City.  This just eased out the now number two, February 1912, which recorded 22.1 inches.

Click here to view Thornton’s February 2015 climate report.

Thornton, Colorado February 2015 Temperature Summary. (ThorntonWeather.com)
Thornton, Colorado February 2015 Temperature Summary. (ThorntonWeather.com)
Thornton, Colorado February 2015 Precipitation Summary. (ThorntonWeather.com)
Thornton, Colorado February 2015 Precipitation Summary. (ThorntonWeather.com)
CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
1124 AM MST MON MAR 2 2015

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

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF FEBRUARY 2015... 

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2015

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................ 
TEMPERATURE (F)
RECORD
 HIGH              77   02/28/2006
                        02/04/1890
 LOW              -25   02/01/1951
                        02/08/1936
HIGHEST            74   02/07        66       8       68  02/16
LOWEST             -6   02/27        -2      -4      -19  02/05
AVG. MAXIMUM     46.6              46.2     0.4     42.3
AVG. MINIMUM     21.0              18.9     2.1     14.1
MEAN             33.8              32.5     1.3     28.2
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      7               3.9     3.1        8
DAYS MIN <= 32     24              26.9    -2.9       26
DAYS MIN <= 0       2               1.3     0.7        5 
PRECIPITATION (INCHES) 
RECORD  
MAXIMUM         2.01   1934  
MINIMUM         0.01   1970 
TOTALS           1.25              0.37    0.88     0.19 
DAILY AVG.       0.04              0.01    0.03     0.01 
DAYS >= .01        10               5.3     4.7        4
DAYS >= .10         5               0.7     4.3        1
DAYS >= .50         0               0.0     0.0        0
DAYS >= 1.00        0               0.0     0.0        0
GREATEST
 24 HR. TOTAL    0.40   02/15 TO 02/16           02/04 TO 02/04

SNOWFALL (INCHES)
RECORDS
 TOTAL           22.4   2015
TOTALS           22.4               5.7

DEGREE_DAYS
HEATING TOTAL     864               908     -44     1022
 SINCE 7/1       4113              4439    -326     4519
COOLING TOTAL       0                 0       0        0
 SINCE 1/1          0                 0       0        0

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

WIND (MPH)
AVERAGE WIND SPEED              9.4
RESULTANT WIND SPEED/DIRECTION   2/205
HIGHEST WIND SPEED/DIRECTION    44/010    DATE  02/21
HIGHEST GUST SPEED/DIRECTION    43/040    DATE  02/04

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            5
NUMBER OF DAYS PC             15
NUMBER OF DAYS CLOUDY          8

AVERAGE RH (PERCENT)     60

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       0
LIGHT RAIN                1     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                4     SNOW                       8
LIGHT SNOW               13     SLEET                      0
FOG                      12     FOG W/VIS <= 1/4 MILE      8
HAZE                      9

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

Denver sets record high temperature for February 6

Record setting high temperatures in Thornton.Denver’s weather rollercoaster this week took us from cold and snow to unseasonably warm temperatures sure to bring an onset of spring fever.  The Mile High City set a record high temperature Friday and may set another Saturday.

As measured at Denver International Airport, today’s office high temperature was 70 degrees.  That easily bests the old record for the date of 67 degrees set in 1944.  Here in Thornton we were just a bit cooler with a high of 69 degrees,

The mild weather will be sticking around for the rest of the weekend with a forecast high of 70 degrees on Saturday (but with some wind) and 66 degrees on Sunday.  The record high for Saturday’s date, February 7, is 71 degrees so we will be coming close to the mark.

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Thornton’s February weather preview: Warmer temps, dry conditions the norm

Thornton and Denver, Colorado February Weather Preview.February in Colorado typically brings to an end an extended period when average temperatures are at their lowest. Winter begins to loosen its grip and temperatures get warmer but precipitation is not a particularly common event during the month.

Probably one of the biggest question marks is whether or not we will see some help with the snow situation.  While mountain snowpack is not in too bad of shape, Denver’s seasonal snowfall to date is well below normal. February is only our sixth snowiest month so it may not provide much help on the precipitation month.

Temperatures however do usually see a nice rebound during the month. Average high temperatures climb from an average of 44 degrees at the start to 50 degrees by the end of February.

For the complete February preview including a look at historical averages and extremes as well as a look at what long range forecasts are predicting, click here. 

January 2015 weather recap: Above normal temperatures, below average precipitation

Look back at last month, we see that Thornton experienced an unusually warm month, one punctuated by a couple rare 70 degree January days.  Precipitation fell short of normal as did snowfall.

The month started out on the cold side with three of the first four days failing to reach temperatures above freezing.  Some light snow was also recorded on the 2nd and 3rd of the month.

We then began a bit of a temperature rollercoaster with above normal readings for two days, a turn toward colder temperatures on the 9th, back to warmth on the next day and then colder than normal for the next four days.

Fourteen of the last 17 days of the month then recorded temperatures at or above normal.  The 26th and 27th saw amazing readings above 70 degrees.

Overall, Thornton’s average temperature for the month came in at 33.7 degrees.  That was well above Denver’s January average of 30.7 degrees.  Out at Denver International Airport where the city’s official records are taken, the month saw a 33.9 degree average.

Thornton’s warmest reading of 74.5 degrees came on the 27th.  Its coldest of -3.7 degrees occurred early in the morning of the 4th.  Denver’s warmest and coldest readings came on the same days.  DIA recorded 75 degrees on the 27th and -10 degrees on the 4th.

In terms of precipitation, 0.20 inches of liquid precipitation was recorded in Thornton.  Denver nearly doubled our number with 0.38 inches. Both locations fell shy of Denver’s January average precipitation of 0.41 inches.

Snowfall in Thornton totaled only 3.5 inches, exactly have of Denver’s January average of 7.0 inches.  Here again the airport bested us with 7.2 inches this January.

Click here to view Thornton’s January 2015 climate report.

Thornton, Colorado temperature summary for January 2015. (ThorntonWeather.com)
Thornton, Colorado temperature summary for January 2015. (ThorntonWeather.com)
Thornton, Colorado precipitation summary for January 2015. (ThorntonWeather.com)
Thornton, Colorado precipitation summary for January 2015. (ThorntonWeather.com)

From the National Weather Service:

CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
614 AM MST SUN FEB 1 2015
 
...................................
 
...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF JANUARY 2015...
 
CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2015
 
WEATHER         OBSERVED          NORMAL DEPART LAST YEAR`S
                 VALUE   DATE(S) VALUE   FROM    VALUE DATE(S)
                                         NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              76   01/27/1888
 LOW              -29   01/09/1875
HIGHEST            75   01/27                         65 01/19
LOWEST            -10   01/04                        -10 01/05
AVG. MAXIMUM     46.7              44.0     2.7     44.9
AVG. MINIMUM     21.0              17.4     3.6     17.3
MEAN             33.9              30.7     3.2     31.1
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      5               5.5    -0.5        4
DAYS MIN <= 32     27              29.4    -2.4       30
DAYS MIN <= 0       3               1.7     1.3        3
 
PRECIPITATION (INCHES)
RECORD
 MAXIMUM         2.35   1883
 MINIMUM         0.01   1933
                        1934
                        1952
TOTALS           0.38              0.41   -0.03     0.94
DAILY AVG.       0.01              0.01    0.00     0.03
DAYS >= .01         5               4.1     0.9        9
DAYS >= .10         1               0.9     0.1        3
DAYS >= .50         0               0.0     0.0        0
DAYS >= 1.00        0               0.0     0.0        0
GREATEST
 24 HR. TOTAL    0.12   01/21
 STORM TOTAL     0.14   01/20(19) TO 01/21(16)
 
SNOWFALL (INCHES)              JANUARY NORMAL
TOTALS            7.2               7.0
 
DEGREE_DAYS
HEATING TOTAL     958              1063    -105     1046
 SINCE 7/1       3249              3531    -282     3497
COOLING TOTAL       0                 0       0        0
 SINCE 1/1          0                 0       0        0
 
FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
..................................................
 
WIND (MPH)
AVERAGE WIND SPEED              9.7
RESULTANT WIND SPEED/DIRECTION   3/229
HIGHEST WIND SPEED/DIRECTION    37/290    DATE 01/17
HIGHEST GUST SPEED/DIRECTION    46/270    DATE 01/05
 
SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            5
NUMBER OF DAYS PC             16
NUMBER OF DAYS CLOUDY         10
 
AVERAGE RH (PERCENT)     62
 
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       0
LIGHT RAIN                1     FREEZING RAIN              0
LT FREEZING RAIN          2     HAIL                       0
HEAVY SNOW                1     SNOW                       4
LIGHT SNOW               12     SLEET                      0
FOG                      16     FOG W/VIS <= 1/4 MILE      6
HAZE                      6
 
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.

Study: Mountain Monitoring System Artificially Inflates Temperature Increases at Higher Elevations

Warming mountain climate?  A new study raises serious questions about the accuracy of the data. (Tony's Takes)
Warming mountain climate? A new study raises serious questions about the accuracy of the data. (Tony’s Takes)

We have all heard the warnings about a warming climate and scientists have claimed to have the data to prove it.  However time and time again the very underlying data has been shown to be faulty.  Here we again find another case.

A new study from the University of Montana shows extreme warming bias in temperature data from critical networks.  The study takes a hard look at climate data gathered across the Rocky Mountain west, including here in Colorado.

“In the context of a warming climate, this artificial amplification of mountain climate trends has likely compromised our ability to accurately attribute climate change impacts across the mountainous western US,” author Jared Oyler writes in his study.

From the University of Montana:

January 12, 2015

MISSOULA – In a recent study, University of Montana and Montana Climate Office researcher Jared Oyler found that while the western U.S. has warmed, recently observed warming in the mountains of the western U.S. likely is not as large as previously supposed.

His results, published Jan. 9 in the journal Geophysical Research Letters, show that sensor changes have significantly biased temperature observations from the Snowpack Telemetry (SNOTEL) station network.

More than 700 SNOTEL sites monitor temperature and snowpack across the mountainous western U.S. SNOTEL provides critical data for water supply forecasts. Researchers often use SNOTEL data to study mountain climate trends and impacts to mountain hydrology and ecology.

Oyler and his co-authors applied statistical techniques to account for biases introduced when equipment was switched at SNOTEL sites in the mid-1990s to mid-2000s. His revised datasets reduced the biases to reveal that high-elevation minimum temperatures were warming only slightly more than minimum temperatures at lower elevations.

“Observations from other station networks clearly show that the western U.S. has experienced regional warming,” Oyler said, “but to assess current and future climate change impacts to snowpack and important mountain ecosystem processes, we need accurate observations from the high elevation areas only covered by the SNOTEL network. The SNOTEL bias has likely compromised our ability to understand the unique drivers and impacts of climate change in western U.S. mountains.”

Co-authors on the paper “Artificial Amplification of Warming Trends Across the Mountains of the Western United States” include UM researchers Solomon Dobrowski, Ashley Ballantyne, Anna Klene and Steve Running. It is available online at http://onlinelibrary.wiley.com/enhanced/doi/10.1002/2014GL062803/.

###

Contact: Jared Oyler, Montana Climate Office, 215-260-4487, jared.oyler@ntsg.umt.edu.

On the net:  Study: US Weather Stations Exaggerated Warming In Western Mountains

State of the Climate 2014: Warmer, wetter than normal in the U.S.

Significant U.S. Weather and Climate Events for 2014. Click for larger view.  (NOAA / NCDC)
Significant U.S. Weather and Climate Events for 2014. Click for larger view. (NOAA / NCDC)

The National Climatic Data Center (NCDC) has released its summary of the nation’s climate and weather for 2014.  Its analysis shows that overall, the United States experienced warmer than normal temperatures and above average precipitation.

From NOAA / NCDC:

2014 U.S. temperature exceeds 20th-century average for the 18th consecutive year

Second warmest December boosted 2014 to 34th warmest year for contiguous U.S; eight weather and climate disasters exceeded $1 billion in damages

The 2014 annual average contiguous U.S. temperature was 52.6°F, 0.5°F above the 20th century average. Very warm conditions dominated the West, with four states having their warmest year on record, while the Midwest and Mississippi Valley were cool. This ranked as the 34th warmest year since we began keeping track in the 1895, while the temperature exceeded the 20th Century average for the 18th consecutive year.

The average contiguous U.S. precipitation was 30.76 inches, 0.82 inch above average, and ranked as the 40th wettest year in the 120-year period of record. The Northern U.S. was wet, and the Southern Plains were dry; the national drought footprint shrank about 2 percent.

In 2014, there were eight weather/climate disaster events with losses exceeding $1 billion each across the United States. These eight events resulted in the deaths of 53 people. The events include: the western U.S. drought, the Michigan & Northeast flooding event, five severe storm events, and one winter storm event.

U.S. climate highlights: 2014

  • The West was warmer than average for much of 2014. Nine states had a top 10 warm year.Alaska, Arizona, California, and Nevada each had their warmest year on record. Most locations from the Rockies to the East Coast were cooler than average, with the exception of New England and Florida. Seven states across the Midwest and Mississippi River Valley had a top 10 cool year. No state was record cold during 2014.
  • The Pacific Northwest, Northern Rockies, Midwest, and Northeast were all wetter than average. Michigan and Wisconsin each had their seventh wettest year on record. The Southern Plains and parts of the Ohio Valley were drier than average, but no state was top 10 dry. The rest of the contiguous U.S. had near-average annual precipitation totals.
  • The U.S. Climate Extremes Index (USCEI) for 2014 was 35 percent above average, ranking as the 19th highest annual USCEI in the 105-year record. The components of the USCEI that were much above average for the year included warm nighttime temperatures and 1-day precipitation totals. The USCEI is an index that tracks extremes (falling in the upper or lower 10 percent of the record) in temperature, precipitation, drought, and land-falling tropical cyclones across the contiguous U.S.
Statewide Average Temperature Ranks for 2014. (NOAA / NCDC)
Statewide Average Temperature Ranks for 2014. (NOAA / NCDC)
Statewide Average Precipitation Ranks for 2014. (NOAA / NCDC)
Statewide Average Precipitation Ranks for 2014. (NOAA / NCDC)

2014 Thornton annual weather recap: Annual temps near normal, above average precipitation

2014 has come to a close and as we look back on the year, we can see that it was a relatively average year lacking too much drama.

In terms of temperatures, Thornton saw an average overall annual temperature of 49.4 degrees.  Out at Denver International Airport where the Mile High City’s official records are kept, the average was warmer at 50.5 degrees.  By comparison, Denver’s 1981 to 2010 annual average temperature is 50.4 degrees.

Thornton recorded 29 days of high temperature readings at or above 90 degrees.  On average Denver sees 40 of them.  Denver matched our number with 29 as well.

The hottest reading of the year was 98.2 degrees which came on July 7.  Denver’s highest reading of 100 degrees came on the same date.

At the other end of the spectrum, our coldest temperature was -12.6 degrees on February 5th.  Denver bested us with two -19 degree readings, one on February 5th and another on December 30th.

In all, Thornton saw 155 days with readings below freezing.  Denver recorded 150.  Both were near the average of 156.9 days.

Precipitation for 2014 came in a good ways above average, largely due to a wet May and July.  Thornton took 19.54 inches into the rain bucket while Denver received slightly less with 18.77 inches.  Both were well above the annual average of 14.30 inches.

Snowfall for the calendar year lagged behind average in both Thornton and Denver.  Thornton saw 46.2 inches of the white stuff, Denver a nearly identical 46.3 inches.  On average we expect to see 53.8 inches.

Click here to view Thornton’s 2014 climate summary report.

Thornton, Colorado 2014 Annual Temperature Summary.
Thornton, Colorado 2014 Annual Temperature Summary.
Thornton, Colorado 2014 Annual Precipitation Summary.
Thornton, Colorado 2014 Annual Precipitation Summary.

From the National Weather Service:

CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
200 AM MST THU JAN 1 2015

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

...THE DENVER CO CLIMATE SUMMARY FOR THE YEAR OF 2014...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2014

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH             105   06/26/2012
                        06/25/2012
                        07/20/2005
                        08/08/1878
 LOW              -29   01/09/1875
HIGHEST           100   07/07        64      36      100  07/11
                                                          06/11
LOWEST            -19   12/30        36     -55      -15  12/05
                        02/05
AVG. MAXIMUM     64.6              64.7    -0.1     63.9
AVG. MINIMUM     36.5              36.3     0.2     36.3
MEAN             50.5              50.5     0.0     50.1
DAYS MAX >= 90     29              39.6   -10.6       54
DAYS MAX <= 32     24              20.0     4.0       29
DAYS MIN <= 32    150             156.9    -6.9      169
DAYS MIN <= 0      14               5.8     8.2       11

PRECIPITATION (INCHES)
RECORD
 MAXIMUM        23.31   1967
 MINIMUM         7.29   2008
TOTALS          18.77             14.30    4.47    17.60
DAILY AVG.       0.05              0.03    0.02     0.05
DAYS >= .01        98              79.7    18.3       82
DAYS >= .10        44              34.9     9.1       42
DAYS >= .50        10               7.6     2.4        8
DAYS >= 1.00        4               2.3     1.7        3
GREATEST
 24 HR. TOTAL    2.85   07/29 TO 07/30             09/13 TO 09/14

 STORM TOTAL       2.93                             4.65
 (MM/DD(HH))      07/29(00) TO 07/30(00)   09/09(00) TO 09/15(00)

SNOWFALL (INCHES)
RECORDS
 TOTAL          115.9   1913
                        0
                        0
 24 HR TOTAL     23.6   12/24/1982 TO 12/24/1982
 SNOW DEPTH        MM   MM
TOTALS           46.3              53.8    -7.5     72.1
 LIQUID EQUIV     MM                MM      MM       MM
SINCE 7/1        16.0              22.5    -6.5      8.1
 LIQUID 7/1       MM                MM      MM       MM
SNOWDEPTH AVG.      0                MM      MM        0
DAYS >= TRACE      55              33.3    21.7       60
DAYS >= 1.0        17              16.3     0.7       20
GREATEST
 SNOW DEPTH         6   12/31                          9  02/25
                        12/30
 24 HR TOTAL      5.4   12/29                    02/24 TO 02/24

 STORM TOTAL      5.9                               11.7
 (MM/DD(HH))      12/29(00) 12/30(00)        03/22(00) TO 03/24(00)

DEGREE_DAYS
HEATING TOTAL    5844              6059    -215     6302
 SINCE 7/1       2291              2468    -207     2451
COOLING TOTAL     701               769     -68      999
 SINCE 1/1        701               769     -68      999

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

WIND (MPH)
AVERAGE WIND SPEED              10.2
RESULTANT WIND SPEED/DIRECTION   2/214
HIGHEST WIND SPEED/DIRECTION    51/310    DATE  07/11
HIGHEST GUST SPEED/DIRECTION    66/340    DATE  04/29

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR           72
NUMBER OF DAYS PC            226
NUMBER OF DAYS CLOUDY         67

AVERAGE RH (PERCENT)     54

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               1
HEAVY RAIN               15     RAIN                      35
LIGHT RAIN               91     FREEZING RAIN              0
LT FREEZING RAIN          2     HAIL                       6
HEAVY SNOW                6     SNOW                      24
LIGHT SNOW               56     SLEET                      1
FOG                     115     FOG W/VIS <= 1/4 MILE     32
HAZE                     57

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

December 2014 weather recap: Temperatures near normal, a bit more than average snow

The month of December started out quiet and quite dry.  Those mild days however gave way to much colder temperatures during the latter half as well as some nice shots of snow.

For the first 13 days of December 2014, Thornton and the Denver area saw temperatures above normal for the most part.  Conditions were dry and calm.  On the 14th, our first storm system came in and delivered a quick, light snowfall.

We then entered a calm period that lasted up until Christmas.  Temperatures got much colder and some cold temperatures records fell.  We also recorded snow on five out of the last seven days of the month.

It was a white Christmas although it wasn’t until late in the day that the white stuff began falling.  Denver’s 3.4 inches on the 25th made it the third snowiest Christmas Day on record.  Thornton recorded 3.1 inches on the day.

The average temperature for the month in Thornton was 29.2 degrees.  Out at the airport, Denver’s official average was a good bit higher at 31.2 degrees.  The long term December average is 30.0 degrees.

Thornton’s temperatures ranged from a high of 64.0 degrees on the 12th down to a bone chilling low of -12.1 degrees on the 30th.  Denver saw a high mark of 66 degrees and a low of -19 degrees on those days.

Two temperature records were set during the month, both on December 30.  A new record low maximum for the date of 1 degree was recorded (old record was 8 degrees set in 1915).  Additionally, Denver’s -19 degrees that day was a new record low (old record was -11 degrees set in 1898).

In terms of precipitation, Thornton recorded 0.48 inches of liquid precipitation.  Denver was a bit wetter with 0.59 inches.  Both readings were above Denver’s December average of 0.35 inches.

On average the Mile High City records 8.5 inches of snowfall during December.  In 2014 the month brought 8.8 inches to Thornton while at the airport Denver recorded 12.0 inches.

Click here to view Thornton’s December 2014 climate report.

Thornton, Colorado December 2014 Temperature Summary.
Thornton, Colorado December 2014 Temperature Summary.
Thornton, Colorado December 2014 Precipitation Summary.
Thornton, Colorado December 2014 Precipitation Summary.

From the National Weather Service:

CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
1041 PM MST THU JAN 1 2015
 
...................................
 
...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF DECEMBER 2014...
 
CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2014
 
WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              79   12/05/1939
 LOW              -25   12/22/1990
                        12/24/1876
HIGHEST            66   12/12        62       4       68  12/18
LOWEST            -19   12/30        -4     -13      -15  12/05
AVG. MAXIMUM     44.1              42.8     1.3     42.9
AVG. MINIMUM     18.5              17.1     1.4     14.0
MEAN             31.3              30.0     1.3     28.4
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      5               5.8    -0.8        8
DAYS MIN <= 32     31              29.4     1.6       29
DAYS MIN <= 0       2               2.0     0.0        6   
PRECIPITATION (INCHES) 
RECORD
  MAXIMUM         5.21   1913
  MINIMUM         0.00   1881 
TOTALS           0.59              0.35    0.24     0.25 
DAILY AVG.       0.02              0.01    0.01     0.01 
DAYS >= .01         7               4.1     2.9        7
DAYS >= .10         2               1.1     0.9        1
DAYS >= .50         0               0.1    -0.1        0
DAYS >= 1.00        0               0.0     0.0        0
GREATEST
 24 HR. TOTAL    0.18   12/29 TO 12/30           12/03 TO 12/04
 
SNOWFALL (INCHES)
RECORDS
 TOTAL           57.4   1913
TOTALS           12.0               8.5
 
DEGREE_DAYS
HEATING TOTAL    1037              1086     -49     1128
 SINCE 7/1       2291              2468    -177     2451
COOLING TOTAL       0                 0       0        0
 SINCE 1/1        701               769     -68      999
 
FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
.....................................................
 
WIND (MPH)
AVERAGE WIND SPEED              8.7
RESULTANT WIND SPEED/DIRECTION   2/218
HIGHEST WIND SPEED/DIRECTION    41/340    DATE  12/23
HIGHEST GUST SPEED/DIRECTION    52/330    DATE  12/23
 
SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            4
NUMBER OF DAYS PC             19
NUMBER OF DAYS CLOUDY          8
 
AVERAGE RH (PERCENT)     59
 
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       1
LIGHT RAIN                1     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                1     SNOW                       4
LIGHT SNOW                8     SLEET                      0
FOG                      12     FOG W/VIS <= 1/4 MILE      3
HAZE                      4
 
-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

White Christmas in Denver? Snow on the holiday not particularly common

For many, the holiday season isn’t complete without a chill in the air and snow on the ground. Here in Denver we historically enjoy a better chance of experiencing the proverbial white Christmas than many places in the nation.

However, how the Mile High City fares in experiencing a white Christmas does depend on your definition of one.

If it means having actual snowfall on Christmas Day the chances aren’t that good. But, if simply having snow on the ground suffices, the chances improve considerably.

For a complete look at Denver’s Christmas weather statistics, click here.

For the latest Thornton weather forecast for Christmas, check out our forecast page.

Historical probability of a white Christmas (at least 1" of snow on the ground).  NOAA / NCDC
Historical probability of a white Christmas (at least 1″ of snow on the ground). NOAA / NCDC