Helena (MT)
September
Weather in Helena, Montana for September 2026
Your guide to Helena weather in September - trends and predictions
In general, the average temperature in Helena at the beginning of September is 25.1 °F. As the month progressed, temperatures tended to moderately fall, reaching an average of 23.9 °F by the end of September.
With an average of 3 rainy days, Helena experiences minimal rainfall in September.
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Temperatures
Rain 🌧️
More
27
Dry days
3
Rainy days
0
Snow days
23°/9°
Temperatures
12 km/h
Avg max wind
48 %
Avg humidity
Helena Weather September
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Temperatures trend during September in Helena
See the weather trend as well as the moving average line
September weather in Helena day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 29° /14° | 0 mm | 7 | |
| Sept. 2 | Sunny | 30° /14° | 0 mm | 8 | |
| Sept. 3 | Sunny | 28° /11° | 0 mm | 7 | |
| Sept. 4 |  Partly cloudy | 20° /9° | 0 mm | 6 | |
| Sept. 5 | Sunny | 19° /4° | 0 mm | 5 | |
| Sept. 6 | Sunny | 23° /5° | 0 mm | 6 | |
| Sept. 7 |  Thundery outbreaks possible | 27° /11° | 0 mm | 6 | |
| Sept. 8 | Sunny | 24° /10° | 0 mm | 6 | |
| Sept. 9 | Thundery outbreaks possible | 24° /10° | 0 mm | 5 | |
| Sept. 10 | Thundery outbreaks possible | 26° /13° | 0 mm | 6 | |
| Sept. 11 |  Overcast | 25° /12° | 0 mm | 6 | |
| Sept. 12 | Thundery outbreaks possible | 20° /7° | 0 mm | 5 | |
| Sept. 13 | Overcast | 21° /8° | 0 mm | 5 | |
| Sept. 14 | Partly cloudy | 24° /8° | 0 mm | 6 | |
| Sept. 15 | Overcast | 15° /10° | 0 mm | 4 | |
| Sept. 16 |  Cloudy | 20° /9° | 0 mm | 5 | |
| Sept. 17 | Sunny | 22° /8° | 0 mm | 6 | |
| Sept. 18 | Sunny | 24° /8° | 0 mm | 6 | |
| Sept. 19 | Overcast | 23° /10° | 0 mm | 5 | |
| Sept. 20 | Sunny | 27° /10° | 0 mm | 7 | |
| Sept. 21 | Overcast | 23° /9° | 20.9 mm | 5 | |
| Sept. 22 | Overcast | 17° /7° | 15.3 mm | 4 | |
| Sept. 23 | Sunny | 24° /4° | 0 mm | 6 | |
| Sept. 24 | Sunny | 26° /6° | 0 mm | 7 | |
| Sept. 25 | Sunny | 27° /10° | 0 mm | 7 | |
| Sept. 26 | Sunny | 19° /8° | 0 mm | 5 | |
| Sept. 27 | Sunny | 24° /5° | 0 mm | 6 | |
| Sept. 28 | Sunny | 25° /7° | 0 mm | 7 | |
| Sept. 29 | Overcast | 26° /9° | 3.6 mm | 6 | |
| Sept. 30 | Cloudy | 20° /10° | 0 mm | 5 | |
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Important Notice
Our weather forecast for Helena 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 Helena forecast closer to your planned date for the most up-to-date weather information.
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Helena in September - FAQ
What are the expected maximum and minimum temperatures in Helena during September?
Enjoy moderate daytime temperatures of up to 23° and cooler nights around 9°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Helena during September?
In September, Helena can expect light to moderate rainfall, totaling 39.8 mm across approximately 3 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in Helena during September?
The average wind speed in Helena during September is 12 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Helena
Explore the daily rainfall trends and prepare for Helenas September weather 💧
Typically, Helena has 3 rainy days in September with a total of 39.8 mm of rainfall.
UV exposure in Helena during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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