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

In September, Gateway Arch National Park averages 29°C high / 15°C low with about 89 mm of rain; Mammoth Cave National Park averages 30°C high / 16°C low with about 107 mm.

Gateway Arch National Park vs Mammoth Cave National Park in September

Gateway Arch National Park is the better pick in September — 81 vs 75 on SeasonMap's comfort score. Gateway Arch National Park is hot, rainy, clean air, while Mammoth Cave National Park is hot, rainy, clean air.

Gateway Arch National Park vs Mammoth Cave National Park — September climate, side by side

	🇺🇸 Gateway Arch National Park	🇺🇸 Mammoth Cave National Park
Comfort score	81/100 (A)	75/100 (B)
Feels-like high	30°C	32°C
Avg high / low	29° / 15°	30° / 16°
Rainfall	89 mm	107 mm
Rainy days	5	6
Humidity	67%	69%
Air quality (AQI)	50	42

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

Month by month

Gateway Arch National Park vs Mammoth Cave National Park in September — FAQ

Is September better in Gateway Arch National Park or Mammoth Cave National Park?: Gateway Arch National Park is the better pick in September — 81 vs 75 on SeasonMap's comfort score. Gateway Arch National Park is hot, rainy, clean air, while Mammoth Cave National Park is hot, rainy, clean air.
What is the weather like in Gateway Arch National Park vs Mammoth Cave National Park in September?: In September, Gateway Arch National Park averages 29°C high / 15°C low with about 89 mm of rain; Mammoth Cave National Park averages 30°C high / 16°C low with about 107 mm.