Monthly climate guide
West Yellowstone weather in September
Expect mild weather in West Yellowstone in September: afternoons reach about 19°C (65°F), while nights drop to around 4°C (39°F). Around 57 mm of rain falls over the month (some rain), and skies are a mix of sun and cloud. Daytime highs are 6°C cooler than August and 10°C warmer than October.
What stands out in September
- Just 440 km apart, but West Yellowstone runs about 5°C cooler than Salt Lake City this month.
- It cools down fast from here: October is about 10°C cooler.
- Afternoons and nights feel like different seasons, roughly 15°C apart.
- Only 2 months are warmer in West Yellowstone than September.
Avg high
19°C
65°F
Avg low
4°C
39°F
Rainfall
57 mm
some rain
Humidity
57%
relative
Sky
43%
cloud · a mix of sun and cloud
West Yellowstone weather by month
Show the monthly averages as a table
| Month | Avg high | Avg low | Rain | Humidity | Cloud cover |
|---|---|---|---|---|---|
| January | -6°C / 21°F | -16°C / 2°F | 77 mm | 99% | 72% |
| February | -5°C / 23°F | -16°C / 4°F | 82 mm | 99% | 73% |
| March | -1°C / 31°F | -11°C / 12°F | 83 mm | 96% | 70% |
| April | 4°C / 40°F | -6°C / 21°F | 80 mm | 84% | 67% |
| May | 12°C / 54°F | 0°C / 32°F | 79 mm | 75% | 67% |
| June | 18°C / 64°F | 4°C / 40°F | 62 mm | 68% | 52% |
| July | 24°C / 76°F | 9°C / 48°F | 39 mm | 57% | 36% |
| August | 24°C / 76°F | 9°C / 47°F | 34 mm | 50% | 39% |
| September | 19°C / 65°F | 4°C / 39°F | 57 mm | 57% | 43% |
| October | 9°C / 48°F | -3°C / 27°F | 60 mm | 70% | 57% |
| November | 0°C / 32°F | -10°C / 14°F | 72 mm | 88% | 69% |
| December | -6°C / 20°F | -17°C / 2°F | 78 mm | 98% | 71% |
What to pack for September
- A warm sweater or fleece for layering
- A mid-weight jacket
- An extra layer — evenings are noticeably cooler than afternoons
- A small travel umbrella, just in case
Is September a good time to visit West Yellowstone?
Compare the months in the chart above to find your ideal window.
Best time to visit West Yellowstone →Other United States cities in September
Cite or embed this data
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West Yellowstone weather in September. WeatherCompare, 2026 (NASA POWER / ERA5, 2011–2020 monthly averages). https://weathercompare.eu/weather/usa/west-yellowstone/september
<a href="https://weathercompare.eu/weather/usa/west-yellowstone/september">West Yellowstone weather in September</a> (WeatherCompare)
<iframe src="https://weathercompare.eu/embed/usa/west-yellowstone" width="300" height="160" style="border:0;border-radius:12px" loading="lazy" title="West Yellowstone weather in September"></iframe> <p style="font-size:12px"><a href="https://weathercompare.eu/weather/usa/west-yellowstone/september">West Yellowstone weather in September</a> – WeatherCompare</p>
West Yellowstone in September: quick answers
Is September a good time to visit West Yellowstone?
Yes. September is one of the best months for West Yellowstone, with highs around 19°C and about 57 mm of rain.
How warm is West Yellowstone in September?
Average highs are about 19°C (65°F) and average lows about 4°C (39°F), based on 10 years of daily data.
Does it rain a lot in West Yellowstone in September?
West Yellowstone typically gets around 57 mm of rain in September — some rain.
Figures are long-term averages for the area around West Yellowstone (NASA POWER / ERA5, 2011–2020), not a forecast for a specific year. For upcoming days, see the live multi-source forecast.