Two days in a row this weekend, Washington, D.C., hit 100 degrees. Overnight lows didn’t drop below 80 degrees for three straight days.
Record temperatures mounted at observing sites in the region, both for scorching daytime temperatures and unusually warm nights.
The humidity made these high temperatures feel even more uncomfortable. The dew point, which is one measure of how much moisture is in the air, has been around or well above 70 degrees since the middle of last week. Dew points below 60 degrees are considered “low humidity.” Even up to 65 degrees, conditions are tolerable. On Saturday, it surged to an obscene 78 degrees in D.C.
Combined, the heat and the humidity led to maximum heat index levels of 110-120 degrees.
Things didn’t cool off at night. The District posted its 5th, 6th and 7th nights this summer with lows remaining 80 degrees or higher, tied for the most on record with 2011. The lows of 81 degrees on Friday and Saturday matched the warmest on record for the month of August. The temperature finally dipped into the upper 70s on Monday morning.
Through Sunday, D.C. has had 38 90-degree days in 2016, which is about eight days more than average for this point in the year.
It’s now the fourth hottest meteorological summer — June through August — in D.C. since records began in 1871, the National Weather Service says. Five of the six hottest summers have occurred since 2010