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Idaho (Coeur d'Alene)
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Weather in Idaho for September 2026

Your guide to Idaho weather in September - trends and predictions

    Temperatures

  • In general, the average temperature in Idaho at the beginning of September is 32 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 22.1 °C by the end of September.

    • Rain 🌧️

  • Idaho experiences moderate rainfall in September, with an average of 10 rainy days and a total precipitation of 32.9 mm.

    • More

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Average dry days
20
Dry days
Average rainy days
10
Rainy days
Average snowy days
0
Snow days
Average temperatures
25°/13°
Temperatures
Average wind speed
11 km/h
Avg max wind
Average humidity
47 %
Avg humidity

Idaho Weather September

Move between months or click on a day
August
October
Mon.Tue.Wed.Thu.Fri.Sat.Sun.
1
Partly cloudy
35°
2
Partly cloudy
34°
3
Cloudy
31°
4
Sunny
31°
5
Sunny
30°
6
Sunny
32°
7
Overcast
31°
8
Partly cloudy
31°
9
Partly cloudy
27°
10
Partly cloudy
26°
11
Moderate rain at times
19°
12
Heavy rain at times
20°
13
Cloudy
24°
14
Patchy rain possible
21°
15
Cloudy
21°
16
Sunny
26°
17
Heavy rain at times
22°
18
Overcast
25°
19
Cloudy
26°
20
Sunny
24°
21
Overcast
20°
22
Overcast
20°
23
Sunny
25°
24
Sunny
28°
25
Patchy rain possible
28°
26
Cloudy
19°
27
Overcast
22°
28
Cloudy
25°
29
Moderate rain at times
18°
30
Sunny
15°

What’s the Weather Like in Idaho This September?

Discover the average temperatures and weather trends across Idaho’s cities this September.
SunnyCoeur d'Alene25 °C / 13 °CSunnyBoise27 °C / 14 °CSunnyIdaho Falls25 °C / 8 °CSunnySandpoint24 °C / 12 °CSunnyLewiston27 °C / 13 °CSunnyTwin Falls28 °C / 11 °CSunnyMeridian28 °C / 13 °CMore Locations

Temperatures trend during September in Idaho

See the weather trend as well as the moving average line

September weather in Idaho day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
Sept. 1 Partly cloudy
Partly cloudy
 35° /18° 0 mm 9
Sept. 2 Partly cloudy
Partly cloudy
 34° /18° 0 mm 9
Sept. 3 Cloudy
Cloudy
 31° /18° 0 mm 8
Sept. 4 Sunny
Sunny
 31° /17° 0 mm 8
Sept. 5 Sunny
Sunny
 30° /14° 0 mm 8
Sept. 6 Sunny
Sunny
 32° /15° 0 mm 8
Sept. 7 Overcast
Overcast
 31° /17° 0 mm 7
Sept. 8 Partly cloudy
Partly cloudy
 31° /14° 0 mm 8
Sept. 9 Partly cloudy
Partly cloudy
 27° /15° 1.4 mm 7
Sept. 10 Partly cloudy
Partly cloudy
 26° /14° 1.8 mm 7
Sept. 11 Moderate rain at times
Moderate rain at times
 19° /13° 6.1 mm 5
Sept. 12 Heavy rain at times
Heavy rain at times
 20° /11° 2.5 mm 5
Sept. 13 Cloudy
Cloudy
 24° /12° 0 mm 6
Sept. 14 Patchy rain possible
Patchy rain possible
 21° /11° 5.5 mm 5
Sept. 15 Cloudy
Cloudy
 21° /9° 1.4 mm 5
Sept. 16 Sunny
Sunny
 26° /9° 0 mm 7
Sept. 17 Heavy rain at times
Heavy rain at times
 22° /14° 3.8 mm 6
Sept. 18 Overcast
Overcast
 25° /13° 0 mm 7
Sept. 19 Cloudy
Cloudy
 26° /13° 0 mm 7
Sept. 20 Sunny
Sunny
 24° /12° 0 mm 6
Sept. 21 Overcast
Overcast
 20° /9° 0.8 mm 5
Sept. 22 Overcast
Overcast
 20° /9° 1 mm 5
Sept. 23 Sunny
Sunny
 25° /10° 0 mm 7
Sept. 24 Sunny
Sunny
 28° /13° 0 mm 7
Sept. 25 Patchy rain possible
Patchy rain possible
 28° /14° 2 mm 7
Sept. 26 Cloudy
Cloudy
 19° /9° 0.1 mm 5
Sept. 27 Overcast
Overcast
 22° /10° 0 mm 5
Sept. 28 Cloudy
Cloudy
 25° /12° 0 mm 7
Sept. 29 Moderate rain at times
Moderate rain at times
 18° /11° 0.4 mm 4
Sept. 30 Sunny
Sunny
 15° /7° 6.2 mm 4
Next
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.
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Idaho in September - FAQ

What are the expected maximum and minimum temperatures in Idaho during September?
Enjoy moderate daytime temperatures of up to 25° and cooler nights around 13°. 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 32.9 mm across approximately 10 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 11 km/h, suggesting breezy to windy conditions, depending on your activities.

September rainfall patterns in Idaho

Explore the daily rainfall trends and prepare for Idahos September weather 💧
Typically, Idaho has 10 rainy days in September with a total of 32.9 mm of rainfall.

UV exposure in Idaho during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
Counties in Idaho
Select a county for an accurate weather forecast
Ada CountyBonner CountyBonneville CountyKootenai CountyNez Perce CountyTwin Falls County
Top locations in Idaho
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BoiseCoeur d'AleneIdaho FallsLewistonMeridianSandpointTwin Falls
More Locations

Quick links

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Location coordinates Where is Idaho?

Get accurate weather forecasts for Idaho, located at latitude 47.678 and longitude -116.78. Stay updated with localized weather information tailored for Idaho.

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