Freeport Weather in September

What's the weather like in Freeport (Illinois) in September 2025?

The climate in Freeport during September can be summarized as mild and a little damp.

September is in the fall / autumn in Freeport and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 23°C (74°F), whilst at night 9°C (49°F) is normal.

Freeport weather averages (imperial / metric)
Daytime temperature 23.3°C 73.9°F
Nightly temperature 9.4°C 48.8°F
Average temperature 16.3°C 61.3°F
Daily sunshine 8 hrs
Avg rainfall 96 mm 3.8 ins
Rainy days 9 days
Sea temperature 18.1°C 64.7°F
Humidity 75%
Windspeed 14.4kph 9 mph

On average September is the 5th wettest month of the year in Freeport with around 96mm 3.8 inches of rain making it a a little damp time to visit. This rainfall is typically spread over 9 days, although this may vary considerably.

On the flip side this corresponds to an average of 8 hours of sunshine per day.

September temperatures in Freeport

Freeport average temperature in September

September rainfall

Freeport average rain in September

September hourly sunshine

Freeport 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 Freeport 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

Freeport weather stats

Freeport weather statistics
Hottest month: July 28.6°C 83.5°F
Driest month: February 31mm 1.2ins
Sunniest month: July 10.7hrs
Coldest month: January -3.3°C 26.1°F
Wettest month: June 114mm 4.5ins
Map showing location of Freeport (42.29669, -89.62123) Freeport map pin © Google

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