What is the weather like in Chicago vs Seattle in September?

In September, Chicago averages 25°C high / 17°C low with about 63 mm of rain; Seattle averages 21°C high / 12°C low with about 36 mm.

Chicago vs Seattle in September

Chicago and Seattle are nearly tied in September — 91 vs 89 on SeasonMap's comfort score. Chicago is warm, a little rain, clean air; Seattle is nice, a little rain, clean air.

Chicago vs Seattle — September climate, side by side

	Chicago	Seattle
Comfort score	91/100 (S)	89/100 (A)
Feels-like high	25°C	21°C
Avg high / low	25° / 17°	21° / 12°
Rainfall	63 mm	36 mm
Rainy days	7	6
Humidity	73%	75%
Air quality (AQI)	45	40

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

Chicago vs Seattle in September — FAQ

Is September better in Chicago or Seattle?: Chicago and Seattle are nearly tied in September — 91 vs 89 on SeasonMap's comfort score. Chicago is warm, a little rain, clean air; Seattle is nice, a little rain, clean air.
What is the weather like in Chicago vs Seattle in September?: In September, Chicago averages 25°C high / 17°C low with about 63 mm of rain; Seattle averages 21°C high / 12°C low with about 36 mm.