March’s Midway Point

The first half of March has been quite warm in the Nation’s Capital with 13 of the first 15 days having been warmer than average.  Consequently, DC’s famous cherry blossoms along the Tidal Basin are likely to reach peak bloom during the next week.  That would be roughly 10 days earlier than the average date.  Peak bloom typically lasts a few days and is defined by the National Park Service as occurring when 70% of the blossoms emerge.

Although no record warmth has occurred so far this month, the combination of warmer than average daily high and low temperatures has also allowed many trees, bushes and flowers to bud.  Although some of the colder suburbs have had freezing temperatures several times this month, temperatures haven’t been at or below freezing in downtown DC since March 1.  

That’s unlike some recent March’s that have been quite cold.  For three consecutive years through 2015, March finished at least 1.5° colder than average.  March 2014 was DC’s coldest since 1996 and snowiest since 1960.  Meanwhile, March 2015 was also the last time temperatures remained below freezing with DC’s high/low temperatures on March 6, 2015 a frigid 30°/15°.

Colder than average March temperatures can impact DC’s cherry blossoms in two primary ways.  They can either delay the arrival of the peak bloom, such as was the case in 2014 and 2015 when peak bloom didn’t arrive until April 10.  The blossoms could also be damaged if temperatures remain in the 20s for several hours once the buds have developed.  Such was the case in March 2017 following a warmer than average winter.  Eight consecutive days of low temperatures below freezing in Washington, D.C. through March 17 caused considerable damage to the buds of the cherry trees.  As a result, roughly half of that springs cherry blossoms were lost.  

While cold weather can delay or damage the blossoms, warm weather can expedite their arrival.  Such was the case in 2008 when peak bloom arrived on March 26 and in 2012 on March 20.  Fortunately, no freezing temperatures are expected during the upcoming week.  This week’s weather will feature more above average temperatures in the DC Metro Area.  Thus, the National Park Service may move up its estimate for peak bloom to occur before the current estimate of March 21 – 24.