How Hot Can June Get?

 

Although summer officially gets underway in June, this month isn’t usually as hot in the Nation’s Capital as it is in July or August.  Nevertheless, there have been some impressive heat waves and extreme heat in the D.C. Metro Area during the month of June.  According to NOAA, June is officially D.C.’s third warmest month of the year. 

The last 10 to 15 years have featured some especially warm and wet June weather in the Nation’s Capital.  Five of D.C’s warmest and three of D.C.’s wettest June’s have occurred just since 2006.  Consequently, there were some noticeable changes when NOAA updated its climate averages last spring (as it does every decade), to reflect the 30-year period of 1991-2020. 

Before last year when NOAA’s climate average reflected the period of 1981-2010, Washington, D.C.’s daily average high/low temperatures ranged from 80°/62° on June 1 to 88°/70° on June 30.  Now since the 30-year period has been updated, with the 2010’s replacing the 1980s, D.C.’s average June temperatures range from 81°/63° on June 1 to 89°/71° on June 30.  That may not sound like a lot but such changes over a decade are important.  Washington, D.C. also averaged 3.78” of June rainfall from 1981-2010, but now averages 4.20” for a roughly 10% increase. 

Washington, D.C. has averaged between seven and eight June days in the 90s dating back to the early 1990s.  Of those days, between one and two featured highs of at least 95°.  D.C. residents have also experienced triple-digit heat roughly once every five years over the last 30 years.  More often than not those rainier than average June’s have also been cooler than average (e.g. 1972, 2003 and 2006).  However, June 2015 was an exception that ranks as D.C.’s second rainiest and sixth warmest.

Longtime Washingtonians may recall that June was an exceptionally hot month in three consecutive years through 2012.  Memorable heat waves occurred in all three June’s (2010 – 2012) and included triple-digit heat.  However, prior to June 2010 no triple-digit June heat had occurred in the Nation’s Capital since 1997.  And none has occurred in nearly a decade when D.C.’s hottest June temperature of 104° occurred on June 29, 2012.  That helps illustrate how streaky June weather can be in Washington, D.C. 

D.C.’s 10 Wettest June’s at Reagan National Airport (DCA: Source - National Weather Service)

1.  14.02”  (2006)
2.  11.94”  (2015)
3.  11.53”  (1972)
4.  10.94”  (1900)
5.  9.97”  (2013)
6.  8.55”  (1883)
7.  7.87”  (2003)
8.  7.53”  (1916)
9.  7.41”  (1929)
10.  7.40”  (1968)

Average: 4.20”

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D.C.’s 10 Warmest June’s (DCA)

1.  80.6°  (2010)
2.  79.4°  (1994)
3.  79.2°  (1943)
4.  78.8°  (2011)
5.  78.7°  (1981)
6.  78.1°  (2015)
7.  77.9°  (2008)
8.  77.6°  (1976)
9.  77.4°  (1925)
10.  77.3°  (2017)

Average: 76.3°

D.C.’s Severe Weather Leaves Its Mark

 

Wind Damage (Photo Credit: Carl Gottlieb)

June has the second highest average annual number of tornadoes (243) in the United States.  Severe weather is defined as a thunderstorm that has any of the following: hail 1” in diameter or greater, wind gusts of at least 58 mph, or a tornado.  The Mid-Atlantic Region has seen many June severe weather outbreaks.  Below are some of the more significant ones that have occurred locally.

2019: June 2 was an active weather day in the D.C. Metro Area with multiple reports of large hail.  Hail as large as 2” in diameter was reported in Damascus, Maryland, as well as 1” diameter hail at the White House.  Having widespread large hail reports in the D.C. Metro Area is relatively uncommon compared to other parts of the country.

2016: On June 21, there were several dozen severe weather reports that included large hail, high wind and a tornado.  An EF-0 tornado, with estimated wind speeds of 80 mph, traveled more than 12 miles in Howard County, Maryland, where minor damage occurred.  Hail nearly 2” in diameter fell at Dulles Airport and several other locations in the D.C. Metro Area.  Also, on June 16 there were several cases of hail at least 2” in diameter in north central Virginia, including the town of Bluemont in Loudoun County.

2013: A total of six EF-0 tornadoes developed on June 13 in the D.C. Metro Area.  Although they were all relatively weak, some occurred in heavily traveled parts of Montgomery and Charles Counties in Maryland and caused minor damage.  This was one of the wettest June’s on record in the Nation’s Capital, with a monthly total of 9.97” of rain at National Airport.

2008:  One of D.C.’s more active severe weather days occurred on June 4.  Unlike the infamous derecho on June 29, 2012, that featured a singular destructive event, there were multiple rounds of severe weather on this date.  The first round was a powerful squall line that passed through the D.C. Metro Area in mid-afternoon.  Later that evening, several supercell thunderstorms developed and some produced tornadoes. 

1996:  On June 24, three tornadoes were reported in northern Virginia.  An F0 tornado touched down in Loudoun County and later the same thunderstorm produced a second tornado.  The second reached F2 intensity in Fairfax County near Sully Station, where the most significant damage occurred.  A third tornado reached F1 intensity in Rockingham County.

Getting Ready for Summer

 

Great Falls, Maryland

May 2022 finished as a warmer and wetter than average month in the Nation’s Capital.  With 6.36” of rain officially at Reagan National Airport, last month finished as D.C.’s 14^th wettest May since weather records began in 1871.  Rain occurred on 18 days last month and that contributed to a gloomy feel to the weather with below average temperatures for much of May.  However, May 2022 finished on a warm note yesterday with a high of 96° at National Airport.  That was D.C.’s hottest May temperature in 11 years since May 31, 2011 (98°). 

NOAA’s Climate Prediction Center expects June to be a warmer than average month in the Nation’s Capital with near average rainfall.  Meteorological summer is comprised of the three-month period of June, July and August.  Daily average high/low temperatures in Washington, D.C. rise from 81°/63° on June 1 to 89°/71° on June 30.  D.C.’s hottest June temperature on record is 104° and occurred on June 29, 2012.  Meanwhile, D.C.’s coolest June temperature is 43° and occurred on June 2, 1897.

While 10 of the last 20 June’s have been warmer than average in Washington, D.C. since 2002, there have been two distinct trends.  Seven of the 10 June’s between 2002 and 2011 were cooler than average in the Nation’s Capital, while seven of the 10 since then were warmer than average.  The earliest in the season it’s been 100° in the Nation’s Capital is June 5 when it was 100° in 1925. 

According to NOAA, June is the second wettest month of the year in the Nation’s Capital with an average of 4.20”.  Three of D.C.’s wettest June’s on record have occurred in the last 16 years.  That includes D.C.’s rainiest June in 2006 and second rainiest June in 2015.  By comparison, June 2017 was D.C.’s third driest with only 1.13”.

Residents of the D.C. Metro Area have also seen their fair share of severe thunderstorms in June.  For example, Maryland’s second strongest tornado on record occurred on June 2, 1998 when an F4 tornado touched down in Frostburg.  The D.C. Area’s infamous “derecho” occurred nearly 10 years ago on June 29, 2012, and caused widespread wind damage and power outages.  More recently, multiple severe hail reports (1”/+ in diameter) occurred on June 2, 2019.  My colleagues and I on the WUSA9 Weather Team are watching the potential for more severe weather in the D.C. Metro Area tomorrow.