The US had remarkable heatwaves during March of 1907 and 1910, which NASA says were the coldest years on record. Almost one day out of five was over 80 degrees during those months.
On March 23, 1910 about three fourths of the US was over 70 degrees.
The graphs below show the spectacular heat. Ashland, Kansas was 100 degrees on March 21, 1907.
Appleton City, Missouri was over 90 degrees on March 19, 20 and 21 1910.