Lake Bluff Weather in September

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

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

September is in the fall / autumn in Lake Bluff and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 23°C (74°F), whilst at night 12°C (54°F) is normal.

Lake Bluff weather averages (imperial / metric)
Daytime temperature 23.3°C 73.9°F
Nightly temperature 12.2°C 53.9°F
Average temperature 17.7°C 63.9°F
Daily sunshine 8 hrs
Avg rainfall 88 mm 3.5 ins
Rainy days 10 days
Sea temperature 19.6°C 67.3°F
Humidity 73%
Windspeed 15.5kph 10 mph

On average September is the 5th wettest month of the year in Lake Bluff with around 88mm 3.5 inches of rain making it a a little damp time to visit. This rainfall is typically spread over 10 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 Lake Bluff

Lake Bluff average temperature in September

September rainfall

Lake Bluff average rain in September

September hourly sunshine

Lake Bluff 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 Lake Bluff 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

Lake Bluff weather stats

Lake Bluff weather statistics
Hottest month: July 27.9°C 82.2°F
Driest month: February 36mm 1.4ins
Sunniest month: July 11hrs
Coldest month: January -2.1°C 28.2°F
Wettest month: July 101mm 4ins
Map showing location of Lake Bluff (42.27891, -87.83424) Lake Bluff map pin © Google

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