On April 21, 1980 it was 100F (38C) at Ada, Minnesota. Over the last 50 years, April temperatures there have plummeted at a rate of nineteen degrees per century. The last time Ada reached 90F during April was 1992.
April temperatures at Ada were stable from 1920 to 1971. Then they rose sharply into the mid 1980’s, and have since plummeted about ten degrees.
