Heat wave in D.C. area is most intense on record this late in year

High temperatures at other local sites are also scorching. So far, it reached 100 degrees at Dulles International Airport, breaking its previous record of 99 in 1988. Baltimore’s BWI Marshall reached at least 101 degrees, breaking its 1988 record of 100.

This ends a 2,867-day streak without reaching or surpassing 100 degrees. It was the fifth longest streak in the modern record for the city, and the longest since an 8-year long run from 1969 to 1977. Other locations in the region had hit 100 more recently than Washington, for instance Dulles did so on Sept. 6 last year.

It becomes the city’s 122nd observed 100-degree day since modern records began in 1872. Roughly 16 percent of D.C.’s 100s have happened in June, 54 percent in July, 27 percent in August and 3 percent in September.

It’s also the sixth day with highs at or above 90, and the eighth of the last 10 reaching that mark, bringing the seasonal total to nine.

That’s about two days above average to date and a quick turnaround from a “90s season” that was running several days below average through the first third of this month. The city averages 40 such days over an entire warm season, seven of which might occur in June.

Although it has been a long while, 100s often come in clumps. In recent years, 2016 had four triple digit days, 2012 eight, 2011 five and 2010 four. In 1930, there were 11 — the most in a single year. Another attempt could be made Sunday and perhaps again Wednesday. This all comes before the city hits prime time for 100s, and as the Weather Service is forecasting a very good chance of a hotter than normal July.

The lengthy gap in 100s followed a historic flurry of them from 2010 to 2012, when 17 were tallied over the three-summer period. While they went missing from 2016 until now, the expectation is that there will be more days at or above 100 annually as the globe warms due to human caused climate change.

D.C.’s highest temperature for any date is 106, reached in July 1930 and August 1918.