The Washington, D.C., region sweated through 10 heat records this weekend.
'Two days in a row this weekend, Washington, D.C., hit 100 degrees. Overnight lows didn’t drop below 80 degrees for a week. We haven’t had heat this intense for this long since 1997.
Perhaps even more uncomfortable, though, was the humidity. 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.
Combined, the heat and the humidity led to a heat index close to 110 degrees.'>>>
https://www.washingtonpost.com/news/capital-weather-gang/wp/2016/08/15/the-washington-d-c-region-sweat-through-10-new-heat-records-this-weekend/