What is the weather like in Boulder vs Yellowstone National Park in September?

In September, Boulder averages 28°C high / 10°C low with about 32 mm of rain; Yellowstone National Park averages 17°C high / 1°C low with about 59 mm.

Boulder vs Yellowstone National Park in September

Boulder is the better pick in September — 90 vs 84 on SeasonMap's comfort score. Boulder is warm, a little rain, clean air, while Yellowstone National Park is cool, a little rain, clean air.

Boulder vs Yellowstone National Park — September climate, side by side

	🇺🇸 Boulder	🇺🇸 Yellowstone National Park
Comfort score	90/100 (S)	84/100 (A)
Feels-like high	26°C	14°C
Avg high / low	28° / 10°	17° / 1°
Rainfall	32 mm	59 mm
Rainy days	4	11
Humidity	53%	59%
Air quality (AQI)	36	43

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

Month by month

Boulder 🇺🇸 United Stateswarm, a little rain, clean air · best September90
Yellowstone National Park 🇺🇸 United Statescool, a little rain, clean air · best August84

Boulder vs Yellowstone National Park in September — FAQ

Is September better in Boulder or Yellowstone National Park?: Boulder is the better pick in September — 90 vs 84 on SeasonMap's comfort score. Boulder is warm, a little rain, clean air, while Yellowstone National Park is cool, a little rain, clean air.
What is the weather like in Boulder vs Yellowstone National Park in September?: In September, Boulder averages 28°C high / 10°C low with about 32 mm of rain; Yellowstone National Park averages 17°C high / 1°C low with about 59 mm.