Weather in Chicago in August 2025
Average weather
Average temperature in Chicago in August
The expected average maximum temperature in August is +28°C with a maximum of +38°C and a minimum of +14°C.
The average maximum temperature goes down 21% by the end of the month, compared with the beginning of the month, from +29°C to +24°C.
Is Chicago warm or cold in August?
Chicago is typically warm in August.
Maximum temperatures go down compared to the previous month from +28°C to +27°C. The minimum temperature also goes down from +21°C to +20°C.
It’s generally warm, but pack a long-sleeve shirt for evenings.
August is one of the warmest months in Chicago, here is the comparison with other months:
Water temperature in Chicago in August
Water in Chicago in August is Comfortable. It varies from +22°C to +25°C, with an average of +23°C. This is almost similar to the air temperature, which averages +27°C.
The water temperature in August is one of the warmest of the entire year:
Can you swim in Chicago in August?
Climate in Chicago in August
| July | August | September | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +28°C | +27°C | +23°C | ||||
| Min. temperature | ||||||
| +13°C | +11°C | +5°C | ||||
| Max. temperature | ||||||
| +40°C | +38°C | +36°C | ||||
| Rainfall | ||||||
| 94 mm | 90 mm | 75 mm | ||||
| Wind | ||||||
| 3 m/s | 3 m/s | 3 m/s | ||||
| Avg. water temperature | ||||||
| +22°C | +23°C | +20°C | ||||
| Humidity | ||||||
| 66% | 69% | 67% | ||||
| Air pressure | ||||||
| 1014 HPa | 1015 HPa | 1016 HPa | ||||
| Sunny days | ||||||
| 4 | 5 | 7 | ||||
| Cloudy days | ||||||
| 10 | 10 | 9 | ||||
| Rainy days | ||||||
| 11 | 12 | 11 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
August weather is still as good as in July. It’s getting colder in August. From +28°C in the day, the average maximum temperature lowers to +27°C. As August arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 94 mm to 90 mm. Humidity rises from 66% to 69%. The average wind speed doesn’t change much during August, staying around 3 m/s. The good news is there are likely to be more sunny days in August, from 4 to 5.
September brings much the same weather, it remains good.
Wind
The average wind speed is 3 m/s getting up to 6 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Chicago is gradually increasing during August, going from 2 m/s to 3 m/s over the course of the month.
Rain
How was the weather last August in Chicago?
Climate Change over Years
The climate in Chicago in August has not changed much over the last 43 years.
The average temperature was the lowest in 1979 (+12°C) and the highest in 2012 (+17°C). The driest year was 2005 with only 501 mm of rainfall, and the wettest year was 2023 with 1535 mm.
FAQ
Is August a good time to visit Chicago?
Can you sunbathe in Chicago in August?
Can you swim in Chicago in August?
Is Chicago rainy in August?
Is it sunny in Chicago in August?
Other cities in USA
Monthly weather in Chicago
Source of the data
For this page, we’ve looked at the typical weather in Chicago, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.