The percentage of the US over 90F on September 16 has plummeted in the US over the last century. During the 1930?, about one fourth of the country was over 90F, but now only about one tenth of the US is over 90F on September 16.
On this date in 1927, almost half of the US was over 90F and 100 degree temperatures were recorded in Indiana, Illinois and Virginia – just west of Washington DC.
