What Can Washingtonians Expect in July?

U.S. Capital, Washington, D.C.  (Source: National Park Service)

Washingtonians know from experience that July often features hazy, hot and humid conditions along with occasional showers and thunderstorms.  Although five of the last six July’s have been warmer than average in the Nation’s Capital, triple-digit heat has only occurred in three July’s since 2000.  July 2010 and July 2011 each featured three days of 100 degree heat, while July 2012 had seven such days – including a streak of four consecutive days above 100 degrees!  Consequently, the summers of 2010 to 2012 were three of the hottest on record. 

The hottest temperature to occur during those torrid summers was on July 7, 2012 – when a record high of 105 degrees was set in Washington, D.C.  That’s just a degree below the all-time record high of 106 degrees – that’s occurred twice in the Nation’s Capital.  July’s hottest temperature last year was 98 degrees on the 19^th.  While average high temperatures in Washington, D.C., are 88 degrees on both July 1 and July 31, it’s 89 degrees from July 7 to 22 – which is the hottest time of the year in the Nation’s Capital on average.  There hasn’t been any triple digit heat in Washington, D.C. since 2012.

Washington, D.C. averages 3.73” of rain in July – the third highest total of the year after May and June.  It’s interesting to note five of the last six July’s have been wetter than average in the Nation’s Capital.  Rainfall amounts can fluctuate depending on the location and frequency of showers and thunderstorms.  Tropical systems can sometimes impact the Mid-Atlantic Region in July and influence rainfall amounts.

In July 1996, Hurricane Bertha made landfall in North Carolina as a Category 2.  It brought significant rainfall to the Mid-Atlantic Region and contributed to making July 1996 almost 2” wetter than average in Washington, D.C.  More recently, Hurricane Arthur gave the Outer Banks of North Carolina a glancing blow in early July 2014, but didn’t impact to the Nation’s Capital.  Having two July hurricanes impact a similar area during the last twenty years shows it's possible – but infrequent.

NOAA’s Climate Prediction Center is expecting July 2016 to be a warmer than average month for the Mid-Atlantic Region.  However, temperatures will not get off to a blazing start with no 90-degree temperatures expected until after the Independence Day holiday.  That’s in stark contrast to July 2012 when the month began with 8 consecutive days of temperatures 95 degrees or hotter.  My colleagues and I on the WUSA9 weather team will continue to keep you apprised of the latest weather forecasts – both on-air and on the free WUSA9 app for your mobile devices.