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Chicago, Illinois Weather in September

Typical September in Chicago, Illinois: days around 76°F, nights around 57°F, and the month cools about 7°F from early to late — based on 30-year climate normals (NOAA, 1991–2020), day by day below.

76°Faverage high

57°Faverage low

−7°Fearly vs late September

18°Fday-to-night swing

Traveling soon? See the live 16-day Chicago forecast →

Early, mid and late September in Chicago

The month split in three — the part of the answer a 30-row table hides.

Part of September	Avg high	Avg low
Early September (Sep 1–10)	79°F	61°F
Mid September (Sep 11–20)	76°F	57°F
Late September (Sep 21–30)	72°F	53°F

Daylight in Chicago during September

How much light the day gives you — useful for planning what you can still do after work.

13 h 08 minon Sep 1

11 h 47 minon Sep 30

−1 h 21 minlost across September

Day-by-day September normals for Chicago

Long-term daily averages (NOAA 1991–2020) — climate, not a live forecast. For the next 16 days, use the live forecast.

Day	Avg high	Avg low
Sep 1	80°F	62°F
Sep 2	80°F	62°F
Sep 3	80°F	62°F
Sep 4	80°F	62°F
Sep 5	79°F	61°F
Sep 6	79°F	61°F
Sep 7	79°F	60°F
Sep 8	78°F	60°F
Sep 9	78°F	60°F
Sep 10	78°F	59°F
Sep 11	77°F	59°F
Sep 12	77°F	59°F
Sep 13	77°F	58°F
Sep 14	76°F	58°F
Sep 15	76°F	58°F
Sep 16	76°F	57°F
Sep 17	75°F	57°F
Sep 18	75°F	56°F
Sep 19	74°F	56°F
Sep 20	74°F	55°F
Sep 21	74°F	55°F
Sep 22	73°F	55°F
Sep 23	73°F	54°F
Sep 24	72°F	54°F
Sep 25	72°F	53°F
Sep 26	72°F	53°F
Sep 27	71°F	52°F
Sep 28	71°F	52°F
Sep 29	70°F	52°F
Sep 30	70°F	51°F

September in Chicago through the years

Real photos taken in Chicago in September by Weathershot app users — different years, same month.

Clear weather in Chicago, 81°F — September 27, 2021 (community photo) — ☀️ Clear · 81°F · Sep 2021📷 BA

Partly cloudy weather in Chicago, 52°F — September 28, 2022 (community photo) — ⛅ Partly cloudy · 52°F · Sep 2022📷 Yousuf M.

Clear weather in Chicago, 79°F — September 1, 2023 (community photo) — ☀️ Clear · 79°F · Sep 2023📷 mmontielg

Cloudy weather in Chicago, 64°F — September 7, 2023 (community photo) — ☁️ Cloudy · 64°F · Sep 2023📷 RayS

Partly cloudy weather in Chicago, 72°F — September 22, 2023 (community photo) — ⛅ Partly cloudy · 72°F · Sep 2023📷 KGM Home Inspection

Weather in Chicago, 79°F — September 20, 2024 (community photo) — 📷 79°F · Sep 2024📷 KGM Home Inspection

Sunny weather in Chicago, 73°F — September 1, 2025 (community photo) — ☀️ Sunny · 73°F · Sep 2025📷 Angelo M. B. G.

Cloudy weather in Oak Park, 82°F — September 3, 2026 (community photo) — ☁️ Cloudy · 82°F · Sep 2026📷 Raymond S.

More months: October · November · December · January · Live Chicago forecast

September elsewhere: Atlanta weather in September · Denver weather in September · Miami weather in September · New York weather in September · Phoenix weather in September · Seattle weather in September

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The September photos above were taken with Weathershot — it stamps the real weather onto your picture. Snap one in Chicago and it could land on this page.

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