We all fixate on record high temperatures for a given location and time, and understandably so, but just as significant, certainly in terms of human health and also in terms of reflecting the climate’s changes, is highest low temperature for a given period.
A case in point: In this heat wave, Mount Washington tied its all time highest low: Overnight Monday, the thermometer never got below 60 degrees. And Burlington, Vermont, set a new record: The thermometer there never got below 80 on Sunday night; the highest low temperature the city has ever recorded.
Could we worse, though: The city of Quriyat in Oman, a small country on the Red Sea, set an all-time record last week; it’s low temperature – low, I said – for the 24 hours was 108.7 degrees. Holy cow.
Why does this matter? Because cooling off at night is an important way that mammals cope with heat waves. We can cope with blistering daytime conditions much better if we can release some of the accumulated heat at night. Remove that nocturnal safety valve and the effects get much worse.