Brentwood Weather in September

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

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

September is in the fall / autumn in Brentwood and is typically the 3rd warmest month of the year. Daytime maximum temperatures average around a comfortable 30°C (85°F), whilst at night 12°C (54°F) is normal.

Brentwood weather averages (imperial / metric)
Daytime temperature 29.5°C 85.1°F
Nightly temperature 12.3°C 54.1°F
Average temperature 20.9°C 69.6°F
Daily sunshine 11.2 hrs
Avg rainfall 6 mm 0.2 ins
Rainy days 2 days
Sea temperature 14.9°C 58.9°F
Humidity 61%
Windspeed 14.4kph 9 mph

On average September is the 4th driest month of the year in Brentwood with around 6mm 0.2 inches of rain making it a very dry time to visit.

On the flip side this corresponds to an average of 11.2 hours of sunshine per day.

September temperatures in Brentwood

Brentwood average temperature in September

September rainfall

Brentwood average rain in September

September hourly sunshine

Brentwood 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 Brentwood 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

Brentwood weather stats

Brentwood weather statistics
Hottest month: July 31.1°C 88°F
Driest month: July 1mm 0ins
Sunniest month: July 13.1hrs
Coldest month: January 12.2°C 54°F
Wettest month: January 81mm 3.2ins
Map showing location of Brentwood (37.92687, -121.72577) Brentwood map pin © Google

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