Chicago's Hot Weather
Dear Tom,
I love hot weather. When does Chicago usually record its first 90-degree day? When
was our last 100-degree day?
--Don Grelecki
Dear Don,
Chicago climate records peg the average date of the city’s first 90-degree day
around May 29 based on 80 years of data from Midway Airport. The earliest 90-
degree day ever recorded here occurred back-to- back on April 10-11, 1930.
In 1875, there were no 90s at all, the only year the city failed to reach that
benchmark, according to other records.
Last year Chicago recorded its first 90-degree day on May 14 and in 2006
it occurred on May 28.
Days with highs in the 100s here are not as common. Our last 100-degree
day was July 24, 2005, when the thermometer officially peaked at 102
degrees. Recent highs in the 100s occurred in 1999 and in 1995, when a deadly
heat wave caused more than 750 fatalities.