Yellowstone County (Billings)
September
Weather in Yellowstone County, Montana for September 2026
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 29.9 °F. As the month progressed, temperatures tended to moderately fall, reaching an average of 27.9 °F by the end of September.
With an average of 2 rainy days, Yellowstone County experiences minimal rainfall in September.
New! Chat with our AI weatherman - it’s amazing and free.
Temperatures
Rain 🌧️
More
28
Dry days
2
Rainy days
0
Snow days
27°/13°
Temperatures
21 km/h
Avg max wind
40 %
Avg humidity
Yellowstone County Weather September
Move between months or click on a day
Temperatures trend during September in Yellowstone County
See the weather trend as well as the moving average line
September weather in Yellowstone County day by day
Click on a date for more information
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 33° /12° | 0 mm | 8 | |
| Sept. 2 | Sunny | 35° /16° | 0 mm | 9 | |
| Sept. 3 |  Overcast | 29° /16° | 0 mm | 7 | |
| Sept. 4 |  Cloudy | 26° /13° | 0 mm | 6 | |
| Sept. 5 | Sunny | 26° /9° | 0 mm | 7 | |
| Sept. 6 | Sunny | 29° /8° | 0 mm | 8 | |
| Sept. 7 | Sunny | 31° /11° | 0 mm | 8 | |
| Sept. 8 | Sunny | 33° /15° | 0 mm | 8 | |
| Sept. 9 |  Partly cloudy | 32° /16° | 0 mm | 8 | |
| Sept. 10 | Overcast | 30° /14° | 0 mm | 7 | |
| Sept. 11 |  Patchy rain possible | 31° /13° | 4.4 mm | 7 | |
| Sept. 12 |  Heavy rain at times | 23° /11° | 4.5 mm | 5 | |
| Sept. 13 | Cloudy | 20° /13° | 31.6 mm | 5 | |
| Sept. 14 | Overcast | 27° /8° | 0 mm | 6 | |
| Sept. 15 | Partly cloudy | 27° /12° | 4.2 mm | 6 | |
| Sept. 16 | Sunny | 22° /11° | 9.6 mm | 6 | |
| Sept. 17 | Patchy rain possible | 25° /13° | 0.1 mm | 6 | |
| Sept. 18 |  Moderate or heavy rain shower | 19° /9° | 29.5 mm | 4 | |
| Sept. 19 | Partly cloudy | 25° /10° | 0 mm | 6 | |
| Sept. 20 | Sunny | 26° /10° | 0 mm | 7 | |
| Sept. 21 | Sunny | 23° /7° | 0 mm | 6 | |
| Sept. 22 | Sunny | 21° /7° | 6.8 mm | 5 | |
| Sept. 23 | Overcast | 24° /7° | 0 mm | 6 | |
| Sept. 24 | Sunny | 27° /8° | 0 mm | 7 | |
| Sept. 25 | Sunny | 31° /11° | 0 mm | 8 | |
| Sept. 26 | Sunny | 27° /13° | 0 mm | 7 | |
| Sept. 27 | Sunny | 28° /7° | 0 mm | 7 | |
| Sept. 28 | Sunny | 29° /9° | 0 mm | 7 | |
| Sept. 29 | Sunny | 31° /11° | 0 mm | 8 | |
| Sept. 30 | Sunny | 22° /8° | 0 mm | 6 | |
| 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.
Change Month
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 ☀️
Top locations in Yellowstone County
Select a location for an accurate weather forecast
More Locations Quick links
More Yellowstone County weather pages
You are here
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.
Found a mistake?
We appreciate your attention to details. Tell us here.