Yesterday's high temperature of 54 degrees was not only our coolest since April 23rd's high of 50 degrees but it also marked one of the largest day-to-day high temperature drops in Philadelphia during the month of October.
One could say yesterday was a slap in the face or even a shock to the system but yesterday's shot of chill and bouts of rain and drizzle were a definite reminder that the cold season isn't far away.
Going back to 1940, the drop in high temperature between Saturday and Sunday was the second largest in the month of October for consecutive days and was the largest drop in 38 years, going back to October 15th and 16th, 1974, when temperatures dropped from 79 to 55 between days. The largest drop for October at the Airport site was between October 2nd and 3rd in 1952, with a high temperature drop of 26 degrees!
For comparison's sake, the next day temperature drop on October 10th, 1979 (our earliest measured snow in Philadelphia) was 22 degrees (64 to 42) so yesterday's drop outperformed the drop from the late 70's. Remarkably enough, both 1979 and 1943 featured two occurrences where the high temperature dropped 20 or more degrees on consecutive days, with the 1943 drops of 23 degrees occurring a week apart from each other!
October is known for fickle, fleeting warmth and occasional, large drops in temperature but our recent drop is even a bit larger than most.