Dear Tom,

Is it true that there was a nearly 50-degree temperature rise in just two minutes in South Dakota?

—Marvin Kuzdas

Dear Marvin,

That huge temperature change occurred Jan. 22, 1943, in the Black Hills at Spearfish, S.D. An arctic air mass was banked up against the Rockies with a layer of mild air over it. As the boundary between the air masses undulated up and down, there was a two-minute 49-degree temperature rise from 4 below zero at 7:30 a.m. to 45 degrees at 7:32 a.m. The wild fluctuations continued with readings falling back to 16 by 12:15 p.m., then rising to 56 at 12:40 p.m. The extreme temperature changes caused some windows to crack.

Chicago's largest short-term temperature change was 22 degrees in 2.5 minutes when a lake breeze on May 9, 1963, dropped readings at Grant Park from 84 to 62 degrees.