Williamsport Weather in September

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

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

September is in the fall / autumn in Williamsport and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 26°C (78°F), whilst at night 12°C (53°F) is normal.

Williamsport weather averages (imperial / metric)
Daytime temperature 25.7°C 78.3°F
Nightly temperature 11.9°C 53.4°F
Average temperature 18.8°C 65.8°F
Daily sunshine 8.6 hrs
Avg rainfall 79 mm 3.1 ins
Rainy days 8 days
Sea temperature 20.5°C 68.9°F
Humidity 73%
Windspeed 13.7kph 9 mph

On average September is the 6th driest month of the year in Williamsport with around 79mm 3.1 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 8.6 hours of sunshine per day.

September temperatures in Williamsport

Williamsport average temperature in September

September rainfall

Williamsport average rain in September

September hourly sunshine

Williamsport 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 Williamsport 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

Williamsport weather stats

Williamsport weather statistics
Hottest month: July 29.7°C 85.5°F
Driest month: February 48mm 1.9ins
Sunniest month: July 10.8hrs
Coldest month: January 0.4°C 32.7°F
Wettest month: May 107mm 4.2ins
Map showing location of Williamsport (40.28837, -87.2939) Williamsport map pin © Google

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