Chicago weather in August
Long-run climate averages for Chicago, IL in August, plus what the forecast models say for the days ahead.
In August, Chicago averages 79°F by day and 64°F at night. It is the wettest month of the year here.
August in Chicago averages a daytime high of 79°F and an overnight low of 64°F, which reads as warm for this part of the world. It is among the three warmest months of the year here. It is also the wettest month, so build rain into any plan. Across the whole year Chicago sees roughly 42 inches of precipitation.
Climate averages tell you what to pack. They do not tell you what next Tuesday looks like - for that, see the live Chicago forecast with every model compared and how much they currently agree.
Chicago weather by month
what to expect in Chicago through the year, 1991-2020 averagesHere is Chicago's typical weather in each month: the average daytime high and overnight low in °F, how each month feels, and the wettest month marked. Use it to plan any trip to Chicago by season.
Bottom line: over the last 30 days the European model has been the most accurate forecast for Chicago, scoring 89/100 on our CheckWeather Score, ahead of the American at 86. See the full US accuracy scoreboard for exactly how every model is tested.
Common questions
How warm is Chicago in August?
Is August a good time to visit Chicago?
Does it rain a lot in Chicago in August?
Climate averages from ERA5 reanalysis. Model accuracy re-scored over a rolling 30 days. Page updated .