A Preview of Denver's January's Weather - The Coldest Month of the Year

Cold and dry are the key words to remember when it comes to January. The month is the coldest of the year and the second driest as well.

Just how cold can January get? The record low temperature for each day of the month is at least 10 degrees below zero. In addition it is not uncommon for the mercury to drop below the freezing mark every night of the month. During the days, the normal high for every day of the month is either 43 or 44 degrees so it never really warms up much. Indeed, the coldest temperature ever recorded in Denver was 29 degrees below zero on January 9th 1875. That isn’t to say though that it can’t get warm – record high temperatures for the month have hit into the 70’s.

Interestingly enough, even though January is the coldest month of the year there is usually not an abundance of inclement weather. It is the second driest month of the year in terms of total precipitation and only the 5th snowiest month. In the not so distant past, an exception to this was in January 1992 when 24.3 inches of snow fell making it the snowiest January in Denver history. In 2006 Denver officially had 15.9 inches of snow (15.0 inches in Thornton) which made it the eighth snowiest January.

January weather can be extremely variable but that of course is a characteristic of any month in Denver. Cold blasts of arctic air usually bring several light snows and sub-zero temperatures to the area. However, chinook winds that warm temperatures into the 50s and 60s are also common. These winds may blow as high as 100 miles per hour in and near the foothills. Boulder and the surrounding area often find themselves under high wind warnings. Chinooks are far more common than blizzards during January.

As it stands today, Thornton has received 39.2 inches of snow this season while the official Denver measurement at DIA is at 37.6 inches. These are considerably above normal as by this point in the snow season Denver averages 25.6 inches. The average total annual snowfall (July through June) for Denver is 61.7 inches so we are in good shape thus far, especially considering our two snowiest months - March and April - are still ahead of us.

Looking back at January 2009

Dry and warm were the keywords for the month of January 2009.  With an average temperature of 34.9 degrees, the month finished 5.7 degrees above normal.  That wasn’t enough for the record books though as the number 10 spot on the ‘top 10’ warmest January’s in Denver was set in 2003 with a 36.9 degree average.  In a rarity, Thornton’s average temperature was the exact same as the Denver average.

Temperatures ranged from a high of 71 degrees down to a bone-chilling cold -11 degrees.  The 71 degree mark set a record for the warmest January temperature on record, beating out the previous mark of 70 degrees last set in 1950.  Thornton bested that mark recording 74.4 degrees on the same day (January 21).  Similarly, Thornton’s coldest temperature was a bit warmer at -5.8 degrees.  Four days had high temperatures below freezing (Thornton had three) which was three less than normal. 

In terms of precipitation, the month did rank in the top 10 driest.  A mere 0.13 inch of precipitation was measured tying it for 10th place on the list with 1925, 1923, 1900 and 1873.   Only three days had measurable precipitation.  Here in Thornton we were a bit wetter with 0.33 inch being recorded.  Similarly, snowfall was meager with only 4.9 inches having fallen throughout the month – 2.8 inches below the normal of 7.7 inches.  Here again Thornton had a bit more with 5.4 inches of snow being recorded at ThorntonWeather.com.  The most snow was received on the 12th when 3.0 inches was recorded.

Click here to see the ThorntonWeather.com January 2009 climate summary.

January 2010 Outlook

The National Weather Service 30-day outlook models do not favor any particular temperature or precipitation pattern for the month. As of this writing however, the Climate Prediction Center's 6 - 10 day and 8 - 14 day outlooks show above normal precipitation is expected. Historical norms listed below should be used for guidance.

For More Information

Temperature Normals and Extremes for January

Monthly Temperature, Rainfall and Snowfall Extremes for January

JANUARY AVERAGE STATISTICS * Normals & Means, 1971 - 2000
TEMPERATURE
AVERAGE HIGH	43.2
AVERAGE LOW	15.2
MONTHLY MEAN	29.2
DAYS WITH HIGH 90 OR ABOVE	0
DAYS WITH HIGH 32 OR BELOW	7
DAYS WITH LOW 32 OR BELOW	30
DAYS WITH LOWS ZERO OR BELOW	4
PRECIPITATION
MONTHLY MEAN	0.51 INCH
DAYS WITH MEASURABLE PRECIPITATION	6
AVERAGE SNOWFALL	7.7 INCHES (5TH SNOWIEST MONTH)
DAYS WITH 1.0 INCH OR MORE SNOWFALL	2
MISCELLANEOUS JANUARY AVERAGES
HEATING DEGREE DAYS	1111
COOLING DEGREES DAYS	0
WIND SPEED (MPH)	8.6
WIND DIRECTION	SOUTH
DAYS WITH THUNDERSTORMS	0 * (* = less than one)
DAYS WITH DENSE FOG	1
PERCENT OF SUNSHINE POSSIBLE	71
JANUARY EXTREMES
RECORD HIGH	76 DEGREES ON 1/27/1888
RECORD LOW	-29 DEGREES ON 1/9/1875
WARMEST	40.3 DEGREES IN 1986
COLDEST	16.9 DEGREES IN 1930
WETTEST	2.35 INCHES IN 1883
MAXIMUM 24 HOUR MOISTURE	1.22 INCHES IN 1883
DRIEST	0.01 INCHES IN 1933, 1934, 1952
SNOWIEST	24.3 INCHES IN 1992
MAXIMUM 24 HOUR SNOWFALL	14.5 INCHES IN 1992
LEAST SNOWIEST	TRACE AMOUNTS 1934 and 2003

* Historical weather statistics gathered from the National Weather Service's Denver / Boulder forecast office data archives.