Yellowstone County (Billings)
September
Weather in Yellowstone County, Montana for September 2025
Your guide to Yellowstone County weather in September - trends and predictions
In general, the average temperature in Yellowstone County at the beginning of September is 31.7 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 27.6 °F by the end of September.
With an average of 2 rainy days, Yellowstone County experiences minimal rainfall in September.
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Temperatures
Rain 🌧️
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28
Dry days
2
Rainy days
0
Snow days
27°/13°
Temperatures
21 km/h
Avg max wind
41 %
Avg humidity
Yellowstone County Weather September
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Temperatures trend during September in Yellowstone County
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September weather in Yellowstone County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 33° /14° | 0 mm | 8 | |
| Sept. 2 | Sunny | 36° /18° | 0 mm | 9 | |
| Sept. 3 |  Overcast | 31° /20° | 0 mm | 7 | |
| Sept. 4 |  Cloudy | 28° /14° | 0 mm | 6 | |
| Sept. 5 | Sunny | 30° /13° | 0 mm | 8 | |
| Sept. 6 | Sunny | 32° /13° | 0 mm | 8 | |
| Sept. 7 | Sunny | 32° /15° | 0 mm | 8 | |
| Sept. 8 | Sunny | 36° /15° | 0 mm | 9 | |
| Sept. 9 |  Partly cloudy | 33° /19° | 0 mm | 8 | |
| Sept. 10 | Overcast | 29° /16° | 0 mm | 6 | |
| Sept. 11 |  Patchy rain possible | 30° /15° | 0.2 mm | 7 | |
| Sept. 12 |  Heavy rain at times | 19° /14° | 9 mm | 4 | |
| Sept. 13 | Cloudy | 21° /12° | 0 mm | 5 | |
| Sept. 14 | Overcast | 27° /11° | 0 mm | 6 | |
| Sept. 15 | Partly cloudy | 29° /12° | 0 mm | 7 | |
| Sept. 16 | Sunny | 28° /13° | 0 mm | 7 | |
| Sept. 17 | Patchy rain possible | 27° /13° | 0.2 mm | 6 | |
| Sept. 18 |  Moderate or heavy rain shower | 14° /11° | 58.9 mm | 3 | |
| Sept. 19 | Partly cloudy | 24° /12° | 0 mm | 6 | |
| Sept. 20 | Sunny | 25° /10° | 0 mm | 7 | |
| Sept. 21 | Sunny | 17° /6° | 0 mm | 5 | |
| Sept. 22 | Sunny | 24° /4° | 0 mm | 6 | |
| Sept. 23 | Overcast | 23° /10° | 0 mm | 5 | |
| Sept. 24 | Sunny | 26° /10° | 0 mm | 7 | |
| Sept. 25 | Sunny | 32° /13° | 0 mm | 8 | |
| Sept. 26 | Sunny | 29° /15° | 0 mm | 7 | |
| Sept. 27 | Sunny | 29° /10° | 0 mm | 7 | |
| Sept. 28 | Sunny | 28° /11° | 0 mm | 7 | |
| Sept. 29 | Sunny | 33° /11° | 0 mm | 8 | |
| Sept. 30 | Sunny | 16° /6° | 0 mm | 5 | |
| Next | |||||
Important Notice
Our weather forecast for Yellowstone County in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Yellowstone County forecast closer to your planned date for the most up-to-date weather information.
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Yellowstone County in September - FAQ
What are the expected maximum and minimum temperatures in Yellowstone County during September?
Enjoy moderate daytime temperatures of up to 27° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Yellowstone County during September?
Moderate rainfall is anticipated in Yellowstone County during September, with a total of 68.4 mm spread over approximately 2 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Yellowstone County during September?
The average wind speed in Yellowstone County during September is 21 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Yellowstone County
Explore the daily rainfall trends and prepare for Yellowstone Countys September weather 💧
UV exposure in Yellowstone County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Yellowstone County?Get accurate weather forecasts for Yellowstone County, located at latitude 45.783 and longitude -108.501. Stay updated with localized weather information tailored for Yellowstone County.
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