Lake Forest Weather in September

What's the weather like in Lake Forest (California) in September 2025?

The climate in Lake Forest during September can be summarized as warm and very dry.

September is in the fall / autumn in Lake Forest and is typically the 2nd warmest month of the year. Daytime maximum temperatures average around a comfortable 26°C (79°F), whilst at night 15°C (60°F) is normal.

Lake Forest weather averages (imperial / metric)
Daytime temperature 26.3°C 79.3°F
Nightly temperature 15.4°C 59.6°F
Average temperature 20.8°C 69.4°F
Daily sunshine 9.8 hrs
Avg rainfall 5 mm 0.2 ins
Rainy days 1 days
Sea temperature 20.4°C 68.8°F
Humidity 69%
Windspeed 12.2kph 8 mph

On average September is the 5th driest month of the year in Lake Forest with around 5mm 0.2 inches of rain making it a very dry time to visit.

On the flip side this corresponds to an average of 9.8 hours of sunshine per day.

September temperatures in Lake Forest

Lake Forest average temperature in September

September rainfall

Lake Forest average rain in September

September hourly sunshine

Lake Forest 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 Forest 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 Forest weather stats

Lake Forest weather statistics
Hottest month: August 26.4°C 79.5°F
Driest month: July 1mm 0ins
Sunniest month: August 11.4hrs
Coldest month: December 18.1°C 64.6°F
Wettest month: January 64mm 2.5ins
Map showing location of Lake Forest (33.64697, -117.68922) Lake Forest map pin © Google

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