Dear Tom,
Is it possible in Chicago to have a wind chill index in the summer?
Len Malcovich, Chicago

Dear Len,

Yes, it’s possible, but it would take chilly conditions for it to occur here. The Chicago National Weather Service posts a wind chill index when temperatures are below 50 degrees. Time of the year is not a consideration. If temps drop into the 40s during the summer, a wind chill may be reported. Chicago has logged many days during meteorological summer (the period of June, July and August) on which the temperature has fallen into the 40s, so the city has reported summer wind chills. These are most likely to occur early in the season. There have been 10 days such days from 2012 through 2021. The most recent occurrence: June 3, 2019, when the temperature dropped to 49 degrees.