A Warm and Dry Start to October

Washingtonians have gotten off to a significantly warmer and drier than average start to October. So far, only two days have featured cooler than average temperatures, while record warmth occurred on four consecutive days.  Also, DC residents finally saw some rain on October 8, which followed a streak of more than three weeks without measurable rainfall.

So far this month, there has been 0.83” of rain at National Airport which, while beneficial, is still below average.  Most of that rain came on October 9 when 0.56” fell – DC’s largest single day rainfall total since September 2 (0.77”).  The Nation’s Capital averages 3.40” of rain in October, so Washingtonians are currently at less than one-fourth of average for the month (0.83”).

Because September was significantly drier than average, the DC Metro area has been quite dry for more than six weeks.  That’s in contrast to July and August which, collectively, finished more than 7” wetter than average.  Over the last 20 years, the Nation’s Capital has had 11 wetter and 11 warmer than average Octobers.

However, four of the last five Octobers have been warmer than average.  This month has continued that trend so far.  The Nation’s Capital has averaged more than three days at/above 80° since 1993, with six such days so far this month.  That’s the highest total since 2007, which was DC’s warmest October on record.  The warmest temperature so far this month was 86° on October 9 and 10.  By comparison, NOAA data indicates 86° is Washington, D.C.’s average high temperature on August 19!

Perhaps this month’s most impressive feat amid all of the warmth was having four consecutive record high-low temperatures (October 8 – 11).  That means that the low temperatures on each of those days remained at record warm levels.  In fact, the low temperature of 75° at National Airport on October 8 not only set a record for the date, but set a record for highest low temperature for the entire month of October.  To help put that into perspective, the average high temperature in Washington, D.C. on October 8 is only 71°.

NOAA expects the warmer than average weather to continue for the next one to two weeks.  By comparison, parts of the western United States and Upper Midwest have already seen their first snowfall of the season.  The Nation’s Capital averages a trace of snow in October (less than 0.01”), with the last occurring on October 29, 2011.  Washingtonians don’t average measurable snowfall until the month of November (0.5”).