The preliminary daily climate report as of 5 pm today shows a high temperature of 101° and a low of 81°. The high has easily broken the old record of 96° for July 24 (set in 1987, 1968, and 1884). The low, assuming it holds through midnight standard time (1 am EDT), will also break the previous record high minimum of 78°, also set in 1987.
Today's record temperatures bring the July month-to-date average up to 83.4°. If it were to hold through the end of the month, this would be a new record hottest July. Given the somewhat less hot temperatures forecast for next week, at least a tie for the record is likely.
The summer season-to-date average of 81.8° is also running well above the pace of the previous hottest summer of 1980.
Image (click to enlarge): Washington, DC average summer temperatures to date for 2010, 1980, 1991, 2002, and climatological period 1971-2000; CapitalClimate chart from National Weather Service data, background photo from Kevin Ambrose
2 days ago