What is the weather like in Indianapolis vs St. Louis in September?

In September, Indianapolis averages 27°C high / 16°C low with about 64 mm of rain; St. Louis averages 29°C high / 15°C low with about 83 mm.

Indianapolis vs St. Louis in September

Indianapolis is the better pick in September — 89 vs 85 on SeasonMap's comfort score. Indianapolis is warm, a little rain, clean air, while St. Louis is hot, rainy, clean air.

Indianapolis vs St. Louis — September climate, side by side

	🇺🇸 Indianapolis	🇺🇸 St. Louis
Comfort score	89/100 (A)	85/100 (A)
Feels-like high	28°C	30°C
Avg high / low	27° / 16°	29° / 15°
Rainfall	64 mm	83 mm
Rainy days	5	5
Humidity	68%	67%
Air quality (AQI)	42	50

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

Month by month

Indianapolis vs St. Louis in September — FAQ

Is September better in Indianapolis or St. Louis?: Indianapolis is the better pick in September — 89 vs 85 on SeasonMap's comfort score. Indianapolis is warm, a little rain, clean air, while St. Louis is hot, rainy, clean air.
What is the weather like in Indianapolis vs St. Louis in September?: In September, Indianapolis averages 27°C high / 16°C low with about 64 mm of rain; St. Louis averages 29°C high / 15°C low with about 83 mm.