West Yellowstone weather in September
Temperature, rain and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Excellent
Best time to visit: June – September
What is the weather like in West Yellowstone in September?
In September, West Yellowstone is mild: daytime highs average 18 °C, and nights cool down to about 5 °C. The sun shines for around 8 hours a day. Rain falls on about 7 days, adding up to 45 mm. All in all, September is an excellent month for a holiday in West Yellowstone.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 97 | 90 | 28 |
| Day | 24° | 18° | 9° |
| Night | 10° | 5° | −2° |
| Sun | 9 h | 8 h | 5 h |
| Rain days | 6 | 7 | 10 |
More details for September
- Daylight
- 12 h 36 min07:02 – 19:38
- UV index
- 6 · highclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 15 km/haverage daily peakAll months
- Cloud cover
- 39 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Snow days
- 1 day1 cm or more of fresh snowAll months
- Time zone
- UTC−6America/Denver
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %75 %
- Few rainy daysweight 30 %82 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Nature escape”.
What to pack in September
- Sunscreen
- Sunglasses & sun hat
- A jumper for the evenings
West Yellowstone in September: quick answers
Is West Yellowstone hot in September?
No. In September, West Yellowstone is mild: daytime highs average 18 °C and nights drop to about 5 °C.
Does it rain much in West Yellowstone in September?
Rain falls on about 7 days, adding up to 45 mm.
West Yellowstone month by month
The whole year in West YellowstoneAll destinations: USAWhere to go in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences