On Sunday, the low temperature was 22 degrees in Aberdeen, South Dakota — that's ten degrees below freezing. The next day, according to the National Weather Service, the high hit 92. That's a swing of 70 degrees in 24 hours.
Over the course of the month, the weather was generally fairly consistent, on the low end of normal temperatures. Fairly suddenly, it jumped up.
Jeff Masters of Weather Underground explains how a sudden midwest heat wave is prompting similar records around the region.
Several cities are poised to experience their greatest 1-day May temperature swing on record today. Chicago bottomed out at 36° on Monday morning, and this afternoon's high is predicted to be 88° — a spectacular 52° change in temperature in just one day. The all-time record for a one-day warm-up in the Windy City during May is 50°, set May 1, 1992. A 50°+ temperature swing is also expected in Minneapolis, where the high today is predicted to be 94°, coming on the heels of a 41° low Monday morning.
Higher temperatures are far more the norm over the past few years. Last year was the hottest year in recorded American history. So far in 2013, nearly 1,000 new high temperatures have been set.
While the increase in Aberdeen is unusual, it's not the biggest 24-hour swing in history. That occurred in Montana in 1972, after the temperature went up 103 degrees overnight. The record for the largest increase in two minutes brings us back to South Dakota. On January 22, 1943, the temperature at 7:30 a.m. was -4. At 7:32, it was 45. Beware the sunbathers.