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.
Read more at Real Climate Science