Gallatin County (Bozeman)
September
Weather in Gallatin County, Montana for September 2026
Your guide to Gallatin County weather in September - trends and predictions
In general, the average temperature in Gallatin County at the beginning of September is 26.3 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 23.1 °F by the end of September.
Gallatin County experiences moderate rainfall in September, with an average of 7 rainy days and a total precipitation of 110.3 mm.
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Temperatures
Rain 🌧️
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23
Dry days
7
Rainy days
0
Snow days
22°/9°
Temperatures
15 km/h
Avg max wind
45 %
Avg humidity
Gallatin County Weather September
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Temperatures trend during September in Gallatin County
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September weather in Gallatin County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 29° /11° | 0 mm | 8 | |
| Sept. 2 |  Partly cloudy | 30° /13° | 0 mm | 8 | |
| Sept. 3 |  Moderate rain at times | 26° /12° | 0.4 mm | 6 | |
| Sept. 4 |  Overcast | 23° /9° | 0 mm | 6 | |
| Sept. 5 | Sunny | 23° /6° | 0 mm | 6 | |
| Sept. 6 | Sunny | 26° /8° | 0 mm | 7 | |
| Sept. 7 | Sunny | 27° /12° | 0 mm | 7 | |
| Sept. 8 |  Cloudy | 26° /11° | 0 mm | 6 | |
| Sept. 9 | Sunny | 26° /12° | 0 mm | 7 | |
| Sept. 10 | Overcast | 27° /10° | 0 mm | 6 | |
| Sept. 11 | Moderate rain at times | 25° /11° | 0.3 mm | 6 | |
| Sept. 12 | Moderate or heavy rain shower | 16° /7° | 7.7 mm | 4 | |
| Sept. 13 | Overcast | 15° /7° | 24.1 mm | 4 | |
| Sept. 14 | Partly cloudy | 22° /7° | 0 mm | 6 | |
| Sept. 15 | Cloudy | 18° /9° | 0 mm | 4 | |
| Sept. 16 | Overcast | 18° /9° | 22.2 mm | 5 | |
| Sept. 17 | Moderate or heavy rain shower | 17° /7° | 6.2 mm | 4 | |
| Sept. 18 | Moderate or heavy rain shower | 15° /7° | 39.6 mm | 4 | |
| Sept. 19 | Cloudy | 21° /8° | 0 mm | 5 | |
| Sept. 20 | Moderate rain at times | 22° /9° | 0.2 mm | 6 | |
| Sept. 21 | Sunny | 18° /6° | 7.5 mm | 5 | |
| Sept. 22 | Cloudy | 15° /5° | 14.4 mm | 4 | |
| Sept. 23 | Overcast | 19° /6° | 0 mm | 5 | |
| Sept. 24 | Sunny | 24° /8° | 0 mm | 6 | |
| Sept. 25 | Sunny | 27° /10° | 0 mm | 7 | |
| Sept. 26 | Overcast | 21° /10° | 0 mm | 5 | |
| Sept. 27 | Sunny | 24° /8° | 0 mm | 6 | |
| Sept. 28 | Sunny | 25° /9° | 0 mm | 7 | |
| Sept. 29 | Sunny | 26° /10° | 2.5 mm | 7 | |
| Sept. 30 | Overcast | 15° /5° | 0 mm | 4 | |
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Important Notice
Our weather forecast for Gallatin 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 Gallatin County forecast closer to your planned date for the most up-to-date weather information.
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Gallatin County in September - FAQ
What are the expected maximum and minimum temperatures in Gallatin County during September?
Enjoy moderate daytime temperatures of up to 22° and cooler nights around 9°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Gallatin County during September?
Significant rainfall exceeding 110.3 mm is expected in Gallatin County during September, occurring over more than 7 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Gallatin County during September?
The average wind speed in Gallatin County during September is 15 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Gallatin County
Explore the daily rainfall trends and prepare for Gallatin Countys September weather 💧
UV exposure in Gallatin County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Gallatin County?Get accurate weather forecasts for Gallatin County, located at latitude 45.68 and longitude -111.039. Stay updated with localized weather information tailored for Gallatin County.
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