September
Weather in Idaho for September 2025
Your guide to Idaho weather in September - trends and predictions
In general, the average temperature in Idaho at the beginning of September is 30.9 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 27.4 °F by the end of September.
Idaho sees moderate rainfall in September, averaging 6 rainy days.
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24
Dry days
6
Rainy days
0
Snow days
26°/14°
Temperatures
16 km/h
Avg max wind
35 %
Avg humidity
Idaho in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  34° | 2  30° | 3 25° | 4 29° | 5 32° | 6  33° | 7  33° |
| 8 32° | 9 31° | 10 28° | 11  22° | 12 16° | 13 20° | 14  26° |
| 15 25° | 16  19° | 17 17° | 18 17° | 19 26° | 20 25° | 21 23° |
| 22 25° | 23 24° | 24 28° | 25 31° | 26 27° | 27 28° | 28 32° |
| 29 25° | 30 21° |
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Temperatures trend during September in Idaho
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September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 | Sunny | 34° /19° | 0 mm | 8 | |
| Sept. 2 | Patchy rain possible | 30° /23° | 0.4 mm | 7 | |
| Sept. 3 | Patchy rain possible | 25° /16° | 0.2 mm | 6 | |
| Sept. 4 | Sunny | 29° /16° | 0 mm | 7 | |
| Sept. 5 | Sunny | 32° /19° | 0 mm | 8 | |
| Sept. 6 | Overcast | 33° /20° | 0 mm | 7 | |
| Sept. 7 | Partly cloudy | 33° /20° | 0 mm | 8 | |
| Sept. 8 | Patchy rain possible | 32° /22° | 1.2 mm | 7 | |
| Sept. 9 | Sunny | 31° /19° | 0 mm | 8 | |
| Sept. 10 | Overcast | 28° /19° | 0 mm | 6 | |
| Sept. 11 | Patchy light rain with thunder | 22° /12° | 2.2 mm | 5 | |
| Sept. 12 | Patchy rain possible | 16° /11° | 3.1 mm | 4 | |
| Sept. 13 | Sunny | 20° /11° | 0 mm | 6 | |
| Sept. 14 | Cloudy | 26° /16° | 0 mm | 6 | |
| Sept. 15 | Cloudy | 25° /17° | 0 mm | 6 | |
| Sept. 16 | Thundery outbreaks possible | 19° /13° | 1.1 mm | 4 | |
| Sept. 17 | Thundery outbreaks possible | 17° /10° | 15.8 mm | 4 | |
| Sept. 18 | Overcast | 17° /11° | 0 mm | 4 | |
| Sept. 19 | Partly cloudy | 26° /13° | 0 mm | 7 | |
| Sept. 20 | Sunny | 25° /11° | 0 mm | 7 | |
| Sept. 21 | Sunny | 23° /9° | 0 mm | 6 | |
| Sept. 22 | Sunny | 25° /8° | 0 mm | 7 | |
| Sept. 23 | Sunny | 24° /10° | 0 mm | 6 | |
| Sept. 24 | Sunny | 28° /12° | 0 mm | 7 | |
| Sept. 25 | Sunny | 31° /14° | 0 mm | 8 | |
| Sept. 26 | Sunny | 27° /14° | 0 mm | 7 | |
| Sept. 27 | Sunny | 28° /12° | 0 mm | 7 | |
| Sept. 28 | Sunny | 32° /14° | 0 mm | 8 | |
| Sept. 29 | Sunny | 25° /11° | 0 mm | 7 | |
| Sept. 30 | Sunny | 21° /7° | 0 mm | 6 | |
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Important Notice
Our weather forecast for Idaho 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 Idaho forecast closer to your planned date for the most up-to-date weather information.
Idaho in September - FAQ
What are the expected maximum and minimum temperatures in Idaho during September?
Enjoy moderate daytime temperatures of up to 26° and cooler nights around 14°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Idaho during September?
In September, Idaho can expect light to moderate rainfall, totaling 24.1 mm across approximately 6 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in Idaho during September?
The average wind speed in Idaho during September is 16 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Idaho
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UV exposure in Idaho during September
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