Mark Albright, from the Dept. of Atmospheric Sciences at the University of Washington writes:
Many of us saw the exaggerated headlines about the “massive heat wave” gripping the USA over the past weekend of 20-21 July 2019:
Well , there is an explanation, it’s called mid-summer.
Climatologically speaking, the two warmest days of the year were this past weekend: July 20 and 21.
Nationwide, Saturday averaged +0.8 F above climatology while Sunday averaged -0.2 F below climatology based on data from the Climate Reference Network:
On Saturday morning, two sites in the Pacific Northwest dropped to below freezing, Stanley ID with 29 F and Meacham OR with 31 F.
And on Sunday morning (21 July 2019) the temperature dropped to 38 F at Great Falls MT, the coldest July temperature of the past twenty years!