How Hot Can It Get ?

As DC’s third hottest month of the year, Washingtonians have seen their fair share of June heat and humidity.  Today is quite tropical with highs this afternoon on the way to being around 90° combined with dewpoint temperatures in the low to mid 70s that will produce a heat index or “feels-like” temperature near 100°.  While uncomfortable and dangerous, today’s highs aren’t near record levels.

DC’s record highs during the month of June are 100°/+ on 12 different days, while they are at least 95° the rest of the month.  While triple-digit heat is relatively uncommon in the Nation’s Capital in June, it has happened 10 times since National Airport opened during World War II.  The most recent incidence of triple-digit heat during June was June 29, 2012 when DC’s record June temperature of 104° was observed.  

The month of June has been quite hot in the DC Metro Area over the last decade, with the last cooler than average June in 2009.  Six of DC’s 10 warmest June’s have occurred just since 2010.  June has actually been hotter than the month of August in the Nation’s Capital five times since 1980.

July is DC’s hottest month of the year overall based on average temperature.  Of July’s 31 days, 28 have record highs of 100° or higher.  DC’s most recent triple digit heat in July occurred on July 25, 2016.  The record for most 100° July days in Washington, D.C. is seven that occurred in 2012.  Eight of DC’s 20 hottest July’s have occurred just since 2010.

August is DC’s second hottest month of the year.  Nineteen of DC’s 31 daily record highs during the month of August are 100°/+.  The most recent triple-digit August heat in the Nation’s Capital was in 2016.  Five of DC’s 10 hottest Augusts have occurred just since 2002.  August has been DC’s hottest month of the year eight times since 2000, most recently in 2018.

Having one really hot summer month doesn’t necessarily mean the entire summer will be extremely hot.  For example, although June 1994 was one of DC’s hottest on record with a 14-day heat wave and July 1994 was also hotter than average, August 1994 finished more than 2° cooler than average.  Conversely, while June 2016 had only five days of 90° in the Nation’s Capital, the 2016 summer finished as one of DC’s hottest on record.  Fortunately for those who don’t care for extreme heat or humidity, my colleagues and I on the WUSA9 weather team don’t have any 90s on the seven-day forecast after today.