May 25th temperatures have been declining in the US since the 19th century, with recent years among the coolest.
On May 25, 1911 most of the US east of the Rockies was above 90 degrees., with 100 degree temperatures in Oklahoma, Illinois and South Carolina.
On May 25, 1967 there was a very intense heatwave centered over Nebraska, with Hartington, Nebraska reaching 107 degrees, and many surrounding states over 100 degrees.
