A Tale of Two Extremes

2018 Has Gotten off to a Frigid Start in Washington, D.C.  (Courtesy: Robin Beal)

The first half of January 2018 has been exceptionally frigid in the Nation’s Capital.  This month’s average temperature (combining daily high and low temperatures) is 29.5° (6.5° below average) through January 17.  That’s despite having three consecutive days in the 60s this past week.  

So far this month, there have been a total of 10 days with low temperatures in the single digits and teens.  High temperatures remained at or below freezing on eight days.  That’s the highest such total since January 2005.  Although no record lows were set in Washington, D.C., temperatures were below average on 13 of the first 17 days this month.

Official weather measurements for Washington, D.C. are made at National Airport.  Some may wonder where weather measurements for the Nation’s Capital were made prior to National Airport’s opening in 1941.  They were taken downtown in Northwest Washington and date back to the 1870s.

 

The vast majority of record low temperatures in the Nation’s Capital occurred before 1941 when measurements were made away from the Potomac River and when the city was much less developed.  The urban heat island effect was significantly less than it is today.  Only a third of the 62 record low January temperatures (including record low and record low-high temperatures) have occurred at National Airport.  

The last time a record low temperature occurred in Washington, D.C. in the month of January was in 1994.  By coincidence, today is the 24^th anniversary of the last time temperatures fell below zero degrees in the Nation’s Capital.  The observed high and low temperatures of 8°/-4° remain January 19 records.  That was also the last time a high temperature remained below 10° in Washington, D.C.  Since then, Washingtonians have had a total of 15 record high January temperatures (including record highs and record high-low temperatures).

Fortunately, for those tired of the cold, NOAA expects warmer than average weather in the DC Metro Region for over the next one to two weeks.  Several days over the next week will feature high temperatures in the 50s, compared to average high temperatures in the low 40s.  This milder than average weather will prevent January from finishing as an exceptionally cold month overall.  While 10 of the last 20 January’s been warmer than average, three of the past four have been colder than average in Washington, D.C.  

Over the last several weeks of up and down temperatures, Washingtonians have had very little snowfall.  Since December 1, DC residents have seen only 3.1” of snow, including 1.2” since January 1.  By comparison, southern cities like Atlanta, Georgia and Birmingham, Alabama received 4.7” and 4” of snow, respectively, since December 1.  That is not good news for local snow lovers.