Chicago weather in September 2025

Expect 24°C daytime maximum temperatures in the shade with on average 8 hours of sunshine per day in Chicago in September. Check more long-term weather averages for Chicago in September before you book your next holiday to Illinois in 2025/2026.

  • 24°C maximum daytime temperature in September in Chicago24
    24°C max day temperature
  • 8 hours of sunshine per day
  • 9 days with some rainfall in September in Chicago9
    9 days with some rainfall
  • 12°C minimum night-time temperature in September in Chicago12
    12°C min night temperature
  • 12 hours of daylight per day in September in Chicago12
    12 hours of daylight per day
  • No heat & humidity in September in Chicago0
    No heat & humidity
  • 87 mm monthly rainfall in September in Chicago87
    87 mm of monthly rainfall
  • UV (maximum) index 6 (High) in September in Chicago6
    6 (High) UV index
  • 19°C sea temperature in September in Chicago19
    19°C sea temperature

More about Chicago

Chicago by month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Recommended for Chicago

Holiday Autos discount code: up to 10% off global car hire

  • Save up to 10% on cheap car hire worldwide
  • Exclusive Holiday Autos discount code automatically applied
  • Travel before 31st December 2024 (inclusive)
Show discount codeShow discount code ******vel
Redeem Holiday Autos discount code >>

Expires at 23:59 on Tuesday 31st Dec 2024 · View all Holiday Autos offers

Holiday AutosCar hire finder

The September weather guide for Illinois (Chicago) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C / mm)  |  Imperial (°F / inches)

Back to top

More about the USA

How hot is it in Chicago in September?

Daytime temperatures usually reach 24°C in Chicago in September, falling to 12°C at night.

How sunny is it in Chicago in September?

There are normally 8 hours of bright sunshine each day in Chicago in September - that's 61% of daylight hours.

How warm is the sea around Chicago in September?

The average sea temperature around Chicago in September is 19°C.

Does it rain in Chicago in September?

There are usually 9 days with some rain in Chicago in September and the average monthly rainfall is 87mm.

Chicago September sunrise & sunset times

Browse the sunrise and sunset times for Chicago in September 2025. Select a month to view Chicago sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 05:17 18:23
Monday, 15th September 2025 05:31 17:59
Tuesday, 30th September 2025 05:47 17:33

Related posts

Popular travel offers

Explore holidays in the sun for less

More holidays

Airport parking

More parking

Airport lounges

More lounges

Top ^