Chicago weather in September
Temperature, rain and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Excellent
Best time to visit: May – September
What is the weather like in Chicago in September?
In September, Chicago is warm: daytime highs average 22 °C, and nights cool down to about 17 °C. The sun shines for around 7 hours a day. Rain falls on about 9 days, adding up to 70 mm. All in all, September is an excellent month for a holiday in Chicago.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 82 | 83 | 63 |
| Day | 26° | 22° | 16° |
| Night | 20° | 17° | 10° |
| Sun | 8 h | 7 h | 5 h |
| Rain days | 11 | 9 | 10 |
More details for September
- Daylight
- 12 h 33 min06:29 – 19:02
- UV index
- 6 · highclear sky, noon (estimate)All months
- Muggy days
- 6 daysdew point 18 °C or moreAll months
- Wind
- 19 km/haverage daily peakAll months
- Cloud cover
- 46 %on averageAll months
- Hot days
- 1 day30 °C or moreAll months
- Snow days
- 0 days1 cm or more of fresh snowAll months
- Time zone
- UTC−5America/Chicago
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %65 %
- Few rainy daysweight 30 %68 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Sunscreen
- Rain jacket or umbrella
Chicago in September: quick answers
Is Chicago hot in September?
Warm rather than hot: in September, daytime highs in Chicago average 22 °C and nights cool to about 17 °C.
Does it rain much in Chicago in September?
Rain falls on about 9 days, adding up to 70 mm.
Chicago month by month
The whole year in ChicagoAll destinations: USAWhere to go in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences