Idaho Falls Weather in September

What's the weather like in Idaho Falls (Idaho) in September 2025?

The climate in Idaho Falls during September can be summarized as mild and dry.

September is in the fall / autumn in Idaho Falls and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 23°C (73°F), whilst at night 5°C (41°F) is normal.

Idaho Falls weather averages (imperial / metric)
Daytime temperature 22.9°C 73.1°F
Nightly temperature 4.8°C 40.6°F
Average temperature 13.8°C 56.8°F
Daily sunshine 10.2 hrs
Avg rainfall 23 mm 0.9 ins
Rainy days 6 days
Sea temperature 15.1°C 59.1°F
Humidity 48%
Windspeed 14.8kph 9 mph

On average September is the 6th wettest month of the year in Idaho Falls with around 23mm 0.9 inches of rain making it a dry time to visit. This rainfall is typically spread over 6 days, although this may vary considerably.

On the flip side this corresponds to an average of 10.2 hours of sunshine per day.

September temperatures in Idaho Falls

Idaho Falls average temperature in September

September rainfall

Idaho Falls average rain in September

September hourly sunshine

Idaho Falls average rain in September

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Idaho Falls in September 2025.

Other monthly averages

Best places to visit in September

UV index Best time to go?

Beta

Current (hourly) weather 15 day forecast

Idaho Falls weather stats

Idaho Falls weather statistics
Hottest month: July 29.6°C 85.3°F
Driest month: July 16mm 0.6ins
Sunniest month: July 13hrs
Coldest month: January -3°C 26.6°F
Wettest month: May 35mm 1.4ins
Map showing location of Idaho Falls (43.46658, -112.03414) Idaho Falls map pin © Google

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