Chicago is a classic humid-continental city pushed around by the Great Lakes. Summers are warm and thundery; winters are properly cold, with Lake Michigan handing the lakefront lake-effect snow bands that the western suburbs rarely see. The lake also cools the shoreline by 10–15°F on hot summer afternoons, which is why Grant Park can feel comfortable while Midway hits the high 90s. Spring is the most volatile season: a single week can swing from snow squalls to a 75°F afternoon to a severe thunderstorm warning.
Climate and Average Weather Year Round in Chicago
Year-round temperature
In Chicago, the warmest months are June through September, with average daily highs between 76°F and 85°F. The coldest stretch runs December through February, with highs between 33°F and 38°F and overnight lows reaching 19°F.
Rainfall through the year
Rainfall in Chicago averages 2.9 in per month over the long run. May is the wettest at 4.1 in, while February is the driest at 1.5 in.
Days at 90 °F or hotter
Chicago averages 20.9 days per year at 90 °F or hotter. The hottest year on record saw 41 such days (2012); the coolest just 3 (2004).
Precipitation this year
As of May 28, Chicago has received 13.9 in of precipitation this year — 15% above the long-term normal for this point in the year (12.1 in).