January Packs a Punch

The new year has gotten off to a mild and wet start in the Nation’s Capital following the sixth consecutive warmer than average December.  But that’s poised to change dramatically, as a shift to colder than average temperatures are on tap later this week.  The average high and low temperatures in Washington, D.C. on New Year’s Day and January 31 are 44 and 29 degrees, respectively.

The coldest time of the year in the Nation’s Capital is from January 12 – 22.  That’s when National Weather Service data shows average high and low temperatures of 43/28 degrees based on a running 30-year average from 1980-2010.  January’s coldest temperature on record in Washington, D.C. is -14 that occurred on January 1, 1881.  Meanwhile, the coldest January temperature at National Airport (that opened in 1941) is -5 degrees that occurred January 17, 1982.  

Six of the last 10 Januarys have been colder than average in Washington, D.C., with January 1994 being the coldest in more than 30 years.  The last time the temperature fell below zero in Washington, D.C. was on January 19, 1994 when it reached -4.  By comparison, Januarys warmest temperature in the Nation’s Capital is 79 degrees that occurred on January 26, 1950. 

Washingtonians average 2.81” of rain and 5.6” of snow in January.  That’s roughly one-third of the 15.4” of snow the Nation’s Capital sees in an entire year.  The wettest January in Washington, D.C. occurred in 1937 (7.83”), while the driest was in 1955 (0.31”).  The snowiest January on record in the Nation’s Capital was in 1922 (31.5”), the year of the infamous “Knickerbocker” Storm.  Washingtonians have had measurable snow every January since 2005.  January 2016 was the snowiest January in the Nation’s Capital since 1996.

It’s important to consider the larger picture when looking at the outlook for January.  Last year featured warmer and drier than average conditions in Washington, D.C. in 10 of 12 months.  2016 also had a rainfall deficit of 8.04”, with 6.57” of that just since September 1.  Going back to August 1, 2015, the rainfall deficit is 11.02”.  So today’s rain combined with what’s expected tomorrow is quite beneficial.  

Although NOAA expects colder than average temperatures for much of the eastern United States late this week into next week, the month is expected to finish warmer than average.  Experts also expect near average monthly precipitation.  Ironically, last January finished within a half a degree of average and only 0.13” drier than average, despite having the fourth largest snowstorm on record.  That shows a major snowstorm can occur in an otherwise benign weather month.  No accumulating snowfall is on the horizon for the DC Metro Region.  My colleagues on the WUSA9 weather team will keep you apprised of the latest weather forecasts both on-air and online.