Pontiac Weather in September

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

The climate in Pontiac during September can be summarized as warm and a little damp.

September is in the fall / autumn in Pontiac and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 25°C (77°F), whilst at night 12°C (54°F) is normal.

Pontiac weather averages (imperial / metric)
Daytime temperature 25.1°C 77.1°F
Nightly temperature 12.2°C 53.9°F
Average temperature 18.6°C 65.5°F
Daily sunshine 8.4 hrs
Avg rainfall 85 mm 3.4 ins
Rainy days 9 days
Sea temperature 20°C 68°F
Humidity 72%
Windspeed 14.4kph 9 mph

On average September is the 5th wettest month of the year in Pontiac with around 85mm 3.4 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 8.4 hours of sunshine per day.

September temperatures in Pontiac

Pontiac average temperature in September

September rainfall

Pontiac average rain in September

September hourly sunshine

Pontiac 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 Pontiac 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

Pontiac weather stats

Pontiac weather statistics
Hottest month: July 29.3°C 84.7°F
Driest month: February 34mm 1.3ins
Sunniest month: July 10.9hrs
Coldest month: January -1.5°C 29.3°F
Wettest month: July 106mm 4.2ins
Map showing location of Pontiac (40.88087, -88.62978) Pontiac map pin © Google

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