May 24 afternoon temperatures have been declining in the US since the 19th century, and the frequency of hot days has plummeted – with recent years being among the coolest on record. On May 24, 1926, temperatures over 100 degrees were reported in South Dakota Nebraska, Arkansas and Arizona. Kennebec, South Dakota was 105 degrees on both May 23 and May 24 that year.
On May 24, 1939, Madison, Indiana was 100 degrees. They had 100 degree weather from May 24 to October 8 that year, and 90 degree weather from April 24 to October 20.
One hundred degree temperatures on May 24, 1939 were recorded in Indiana, Missouri, Iowa, Nebraska, Kansas, Oklahoma and Texas.