Crystal Lake Weather in September

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

September is in the fall / autumn in Crystal Lake and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 23°C (74°F), whilst at night 11°C (52°F) is normal.

On average September is the 5th wettest month of the year in Crystal Lake with around 92mm 3.6 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.

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 Crystal Lake in September 2025.