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Climate · Chicago

Chicago in September

Warm and damp, as the days shorten.

Typical weather, averaged over 30 years

September in Chicago is warm: highs near 77°F, lows near 63°F. Rain falls on about two days a week, more often as the month goes on, and the days shorten by 1 hour 1 minute from the first week to the last.September in Chicago is warm: highs near 25°C, lows near 17°C. Rain falls on about two days a week, more often as the month goes on, and the days shorten by 1 hour 1 minute from the first week to the last.

High
77°F25°Caverage
Low
63°F17°Caverage
Wet days
2a week · 32% of days
Daylight
12h 23mon average

Is September a good time to visit Chicago?

Yes. September is one of Chicago's best months (June, or September).

How we judge it: every month is scored on how close its typical high comes to the range from 70°F to 80°F, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.How we judge it: every month is scored on how close its typical high comes to the range from 21°C to 27°C, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.

How September sits in the year

week by week

Temperature

Highs near 77°F in September, against 35°F to 84°F through the year.Highs near 25°C in September, against 2°C to 29°C through the year.

Chance of a wet day

32% of days in September, against 32% to 43% through the year.

Cloud cover

36% cover in September, against 36% to 63% through the year.

Daylight

12h 23m in September, against 9h 11m to 15h 10m through the year.

Week by week, lightly smoothed, with September shaded. The olive line marks the best months. Hover or tap a week for its figures.

Either side

  1. August83°28°low 69°low 21°3 wet days a weekRain on about three days a week.
  2. September77°25°low 63°low 17°2 wet days a weekRain on about two days a week.
  3. October66°19°low 53°low 12°2 wet days a weekRain on about two days a week.

Where Chicago sits, in September

America/Chicago
this place
typical high in September 40°F4°C95°F35°C
Sunrise, mid-September
6:29 AMsets 7:02 PM
Above the sea
175 mlow-lying
Latitude
41.9°Nnorthern hemisphere
Nearest of ours
Dubuque259 km west

The land around Chicago, shaded by its typical high in September, the planning map's own layer. Hover the map for the figure at that spot; tap it on a phone. Clock times are local, for the 15th.

Elsewhere in United States in September

high · low · wet days
See September on the planning mapThe whole year in Chicago

Typical weather, averaged over 30 years (1995–2024), from the 11 km grid square nearest Chicago. Temperatures are adjusted against 66 weather stations: daytime highs read about 3.1°F cold in the source data and are raised to match.Temperatures are adjusted against 66 weather stations: daytime highs read about 1.7°C cold in the source data and are raised to match. Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not. Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.

Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not.

Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.