What is the weather like in Chicago vs Gateway Arch National Park in September?

In September, Chicago averages 25°C high / 17°C low with about 63 mm of rain; Gateway Arch National Park averages 29°C high / 15°C low with about 89 mm.

Chicago vs Gateway Arch National Park in September

Chicago is the better pick in September — 91 vs 81 on SeasonMap's comfort score. Chicago is warm, a little rain, clean air, while Gateway Arch National Park is hot, rainy, clean air.

Chicago vs Gateway Arch National Park — September climate, side by side

	🇺🇸 Chicago	🇺🇸 Gateway Arch National Park
Comfort score	91/100 (S)	81/100 (A)
Feels-like high	25°C	30°C
Avg high / low	25° / 17°	29° / 15°
Rainfall	63 mm	89 mm
Rainy days	7	5
Humidity	73%	67%
Air quality (AQI)	45	50

Monthly climate normals (ERA5 reanalysis). Comfort scores are SeasonMap estimates.

Month by month

Chicago vs Gateway Arch National Park in September — FAQ

Is September better in Chicago or Gateway Arch National Park?: Chicago is the better pick in September — 91 vs 81 on SeasonMap's comfort score. Chicago is warm, a little rain, clean air, while Gateway Arch National Park is hot, rainy, clean air.
What is the weather like in Chicago vs Gateway Arch National Park in September?: In September, Chicago averages 25°C high / 17°C low with about 63 mm of rain; Gateway Arch National Park averages 29°C high / 15°C low with about 89 mm.