Bonneville County (Idaho Falls)
September
Weather in Bonneville County, Idaho for September 2026
Your guide to Bonneville County weather in September - trends and predictions
Until now, September 2026 in Bonneville County is slightly cooler than the historical average by 1.1 °F.
The forecast for the upcoming days in Bonneville County predicts a temperature of 23.6 °F, which is slightly above the historical average.
In general, the average temperature in Bonneville County at the beginning of September is 29.3 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 22.1 °F by the end of September.
With an average of 5 rainy days, Bonneville County experiences minimal rainfall in September.
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Temperatures
Rain 🌧️
More
25
Dry days
5
Rainy days
0
Snow days
25°/8°
Temperatures
21 km/h
Avg max wind
44 %
Avg humidity
Bonneville County Weather September
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Temperatures trend during September in Bonneville County
See the weather trend as well as the moving average line
September weather in Bonneville County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 32° /11° | 6.5 mm | 6 | |
| Sept. 2 |  Cloudy | 30° /11° | 0 mm | 6 | |
| Sept. 3 |  Moderate rain at times | 28° /11° | 0.2 mm | 6 | |
| Sept. 4 | Sunny | 28° /10° | 0 mm | 8 | |
| Sept. 5 | Sunny | 29° /9° | 0 mm | 8 | |
| Sept. 6 | Sunny | 30° /9° | 0.1 mm | 8 | |
| Sept. 7 |  Partly cloudy | 28° /10° | 0 mm | 8 | |
| Sept. 8 | Sunny | 29° /7° | 0 mm | 7 | |
| Sept. 9 | Sunny | 29° /9° | 0 mm | 7 | |
| Sept. 10 |  Overcast | 29° /10° | 0 mm | 7 | |
| Sept. 11 |  Patchy rain possible | 27° /13° | 0.2 mm | 6 | |
| Sept. 12 | Patchy rain possible | 22° /7° | 1.1 mm | 5 | |
| Sept. 13 | Sunny | 23° /9° | 0 mm | 6 | |
| Sept. 14 | Overcast | 23° /6° | 0.1 mm | 6 | |
| Sept. 15 | Cloudy | 23° /7° | 0 mm | 5 | |
| Sept. 16 |  Heavy rain at times | 25° /7° | 0.5 mm | 6 | |
| Sept. 17 | Heavy rain at times | 22° /7° | 6 mm | 4 | |
| Sept. 18 | Moderate rain at times | 21° /7° | 4.3 mm | 4 | |
| Sept. 19 | Sunny | 22° /6° | 0.5 mm | 5 | |
| Sept. 20 | Sunny | 23° /6° | 0 mm | 6 | |
| Sept. 21 | Sunny | 22° /6° | 2.2 mm | 6 | |
| Sept. 22 | Sunny | 20° /7° | 4.8 mm | 4 | |
| Sept. 23 | Sunny | 24° /9° | 0 mm | 5.6 | |
| Sept. 24 | Sunny | 27° /12° | 0 mm | 5.7 | |
| Sept. 25 | Sunny | 26° /12° | 0 mm | 5.3 | |
| Sept. 26 | Sunny | 24° /11° | 0 mm | 5 | |
| Sept. 27 | Overcast | 25° /10° | 0.1 mm | 6 | |
| Sept. 28 | Patchy rain possible | 13° /7° | 7.3 mm | 3 | |
| Sept. 29 | Sunny | 17° /5° | 0 mm | 5 | |
| Sept. 30 | Sunny | 23° /7° | 0 mm | 6 | |
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Important Notice
Our weather forecast for Bonneville 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 Bonneville County forecast closer to your planned date for the most up-to-date weather information.
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Bonneville County in September - FAQ
What are the expected maximum and minimum temperatures in Bonneville County during September?
Enjoy moderate daytime temperatures of up to 25° and cooler nights around 8°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Bonneville County during September?
In September, Bonneville County can expect light to moderate rainfall, totaling 22.1 mm across approximately 5 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in Bonneville County during September?
The average wind speed in Bonneville County during September is 21 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Bonneville County
Explore the daily rainfall trends and prepare for Bonneville Countys September weather 💧
Typically, Bonneville County has 5 rainy days in September with a total of 22.1 mm of rainfall.
UV exposure in Bonneville County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Bonneville County?Get accurate weather forecasts for Bonneville County, located at latitude 43.467 and longitude -112.034. Stay updated with localized weather information tailored for Bonneville County.
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