Chicago Weather in September
United States · Humid Continental climate · Data averaged from 2020-01-01 to 2024-12-31 (5 years)
September in Chicago sees average temperatures ranging from a low of 15.8°C (60.4°F) to a high of 23.8°C (74.8°F), with a mean of 19.6°C (67.3°F). Compared to the annual average of 10.9°C (51.6°F), this month is 8.7°C warmer than the yearly norm. Precipitation averages 98.2mm, making it approximately 4.0mm wetter than the monthly average of 94.0mm. The city receives an average of 9.6 hours of sunshine per day during September, with relative humidity averaging 71.9%. Wind speeds reach an average maximum of 23.6 km/h. For travelers, this month offers a temperature experience in Chicago, with wetter-than-average conditions compared to the rest of the year.
There's something about Chicago in January that reveals the city's true character. I visited during the polar vortex — minus 25°C, Lake Michigan frozen at the edges, and the locals still walked to their neighborhood taverns as if nothing was unusual. The cultural calendar thrives in winter: theaters full, restaurants cozy, museums uncrowded. Summer (June-August) is when Chicago reclaims its lakefront — 25°C, festivals every weekend, the energy electric. I love October: 14°C, the city in autumn colors, and a melancholy knowing winter is coming. Each season reveals a different Chicago.
September vs Adjacent Months
| Metric | August | September | October |
|---|---|---|---|
| Mean Temp | 22.9°C (73.2°F) | 19.6°C (67.3°F) | 12.9°C (55.2°F) |
| Rainfall | 103.5mm | 98.2mm | 115.0mm |
| Sunshine | 11.6 hrs | 9.6 hrs | 7.8 hrs |
| Humidity | 74.9% | 71.9% | 71.0% |
| Wind | 21.8 km/h | 23.6 km/h | 26.8 km/h |
| Rainy Days | 16.8 | 12.4 | 15.6 |
| Snowfall | 0.0 cm | 0.0 cm | 0.6 cm |
Seasonal Context
September falls in Autumn in the Northern Hemisphere. Autumn sees temperatures gradually cooling from summer highs. For travelers visiting Chicago in September, the data indicates favorable conditions based on the combination of temperature, precipitation, and daylight hours.
Frequently Asked Questions
What is the average temperature in Chicago in September?
The average temperature in Chicago during September ranges from 15.8°C (60.4°F) to 23.8°C (74.8°F), with a mean of 19.6°C (67.3°F).
How much does it rain in Chicago in September?
Chicago receives an average of 98.2mm of precipitation in September, spread across approximately 12.4 rainy days.
What should I pack for Chicago in September?
Based on September weather data, pack layers including light jackets and t-shirts, plus an umbrella.
Is September a good time to visit Chicago?
September is a good time to visit Chicago, with comfortable temperatures and manageable rainfall.
Other Months for Chicago
Cities with Similar September Climate (Humid Continental)
Data Source: Open-Meteo historical archive (2020-01-01 to 2024-12-31). Daily measurements aggregated into monthly climate normals. Coordinates: 41.88°, -87.63°. Timezone: America/Chicago. Last updated: 2026-07-30.