Indianapolis Weather in September

What's the weather like in Indianapolis (Indiana) in September 2025?

The climate in Indianapolis during September can be summarized as warm and reasonably dry.

September is in the fall / autumn in Indianapolis and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 26°C (78°F), whilst at night 13°C (55°F) is normal.

Indianapolis weather averages (imperial / metric)
Daytime temperature 25.5°C 77.9°F
Nightly temperature 12.7°C 54.9°F
Average temperature 19.1°C 66.4°F
Daily sunshine 8.5 hrs
Avg rainfall 75 mm 2.9 ins
Rainy days 8 days
Sea temperature 21.7°C 71°F
Humidity 74%
Windspeed 13.3kph 8 mph

On average September is the 4th driest month of the year in Indianapolis with around 75mm 2.9 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 8 days, although this may vary considerably.

On the flip side this corresponds to an average of 8.5 hours of sunshine per day.

September temperatures in Indianapolis

Indianapolis average temperature in September

September rainfall

Indianapolis average rain in September

September hourly sunshine

Indianapolis 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 Indianapolis 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

Indianapolis weather stats

Indianapolis weather statistics
Hottest month: July 29.6°C 85.3°F
Driest month: January 61mm 2.4ins
Sunniest month: July 10.3hrs
Coldest month: January 0.7°C 33.3°F
Wettest month: July 119mm 4.7ins
Map showing location of Indianapolis (39.76838, -86.15804) Indianapolis map pin © Google

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