Dear Tom,
I saw your statistic about the large number of days that have passed without a 70-degree temperature here in Chicago.
Could you expound?
John Meyers
Dear John,
Chicagoans are growing increasingly anxious for at least a hint of spring warmth. And it’s no wonder: The city’s temperature last reached 70 degrees on Oct. 21 — 172 days ago — and the interval since that warmweather benchmark continues to expand as one chilly day follows another in a spring characterized, so far at least, by subnormal temperatures. On average, Chicago experiences its first 70-degree day on March 26 (although that occurrence is delayed until April 9 in the immediate vicinity of Lake Michigan). The average number of days between autumn’s last and spring’s first 70-degree day is 143, and the record interval is 185 days (Oct. 21-April 22, 1943-44).
