Record June Heat Slams D.C. Metro

 

Record high temperatures were set at all three D.C. Area airports on Friday, June 17.  Although summer officially gets underway in June, this month typically isn’t as hot as July and August.  However, there are some notable exceptions.

Such was the case yesterday when record heat was experienced across the entirety of the D.C. Metro Area.  The high of 99° was D.C.’s hottest June day in nearly 10 years.  The last time it was 99° or hotter in the Nation’s Capital during the month of June was on June 29, 2012 (104°).  No June has had more than one day of 100° heat in the Nation’s Capital.

D.C.’s two warmest June’s are good examples of the rare exception when June isn’t the “coolest” of the three unofficial months of summer.  June 1994 featured a 14-day heat wave from June 13 – 26 that was the longest of the summer.  The hottest day was June 15 with a record high temperature of 101°.  A total of five record highs were set during the month, including three consecutive records from June 14 – 16 that still stand.   With a monthly average temperature of 79.4° (combining daily high/low temperatures), June 1994 was warmer than August 1994 (75.5°).

June 2010 was even hotter.  With a monthly average temperature of 80.6°, June 2010 was hotter than August 2010 (80.2°).  June 2010 featured 18 days of 90° heat, with an 11-day heat wave from June 19 – 29.  Six of those 18 days had high temperatures of 95°/+.  D.C. residents had a record high of 100° on June 24.  The summer of 2010 remains the hottest on record in the Nation’s Capital with an average temperature (for June, July and August) of 81.3°. 

Yesterday’s heat was memorable in the Nation’s Capital for not only setting daily records but and was D.C.’s hottest temperature since July 20, 2020 (also 99°).  While it hasn’t been 100° in the Nation’s Capital during the month of June since 2012, it has been 100° more recently not during the month of June.  Although Washington, D.C. hasn’t been 100° since August 15, 2016; Dulles Airport reached 100° more recently on July 21, 2019. 

June 17 Record Highs (Source: National Weather Service)

Washington, D.C. (National Airport: DCA) – 99° (old record 97°: 2014)
Dulles Airport, Sterling, Virginia – 96° (old record 92°: 1994)
Baltimore, Maryland (BWI Airport) – 96° (tied existing record of 96°: 1939)

Memorable June Tropical Systems

 

Tropical Storm Debby, June 2012  (Source: NOAA)

Hurricane season in the Atlantic Ocean Basin runs from June 1 through November 30.  June and November are typically the quietest months of the season when atmospheric and environmental conditions are the least favorable for development.  That’s not to say there haven’t been a few high impact tropical storms and hurricanes in June as described below.

Debby (2012):  Tropical Storm Debby was an example of how a tropical system doesn’t have to be intense to have significant impacts.  Both tropical storms and minimal hurricanes have the potential to bring copious rainfall, along with coastal flooding and beach erosion.  Such was the case with Debby across much of central and northern Florida, where isolated rainfall totals of more than 20” were observed.  The heavy rain attributed to Debby and its remnants helped make June 2012 the wettest June on record in Tampa with a monthly total of 18.66”.

Allison (2001):  While it was only a tropical storm when it made landfall in Texas, Allison achieved a dubious honor.  It was the first of only two Atlantic tropical storms to have had its name retired by the World Meteorological Organization for being both damaging and deadly.  What made Allison unique wasn’t its intensity, but its longevity.  After making landfall in Texas, its remnants lingered for days and caused devastating flooding.  Not until Hurricane Harvey in August 2017 did Texas residents see comparable flooding.

Agnes (1972):  As a weaker tropical storm, Agnes menaced much of the Mid-Atlantic and northeastern United States where its remnants caused widespread flooding.  Multiple June rainfall records were set from Virginia to New York, including D.C.’s wettest June day overall (6.11” on June 21, 1972).  Agnes subsequently had its name retired.  It was a Category 1 hurricane at peak intensity.

Alma (1966):  This was the last Category 3 hurricane that developed anywhere in the Atlantic Ocean Basin during the month of June.  At peak intensity, Alma had sustained winds of 125 mph when it passed over the Florida Keys.  It weakened, however, as it tracked north and ultimately made landfall as a Category 1 hurricane in the Florida panhandle.  Had a similar storm occurred now, the impacts would be much more significant since Florida’s population and coastal development have increased dramatically in the decades since Alma.

Hurricane intensity is ranked on the Saffir-Simpson Hurricane Wind Scale, with a Category 1 being a “minimal” hurricane with sustained winds speeds of 74 to 95 mph.  A hurricane becomes “major” when sustained winds reach 111/+ mph, making it a Category 3.  The strongest hurricanes are Category 5’s, with sustained winds of at least 157 mph.

Weather Quiz

 

True or False.

June is the second warmest month of the year in the Nation’s Capital.