The D.C. government’s Department of Energy and Environment cited fine-particle pollution — the kind produced by fires.
For much of the day, an atmospheric current of wildfire residue, borne here over an undulating route by the jet stream, transformed the look of our skies.
Oddly white at midday, the sky seemed to paint itself a rusty red at sunrise and sunset.
In the meantime, the mercury reached 94 in Washington. It was the third 94-degree day here this month. That reading was the second highest here this year, outstripped only by the 95 of June 30.
The temperature of 94 was also 12 degrees below the record for the date, the 106 degrees reached here on July 20, 1930.
That 106-degree temperature was observed only once before, on Aug. 6, 1918. It is the highest ever officially recorded here.
On the historically hot day 91 years ago, Herbert Hoover occupied the White House.
It was a Sunday, and a story in the next day’s editions of The Washington Post told of his efforts to keep cool. It said that like most other Washingtonians, he spent the day trying to find relief under an electric fan.