Portola Valley Weather in August

What's the weather like in Portola Valley (California) in August 2025?

The climate in Portola Valley during August can be summarized as mild and very dry.

August is in the summer in Portola Valley and is typically the warmest month of the year. Daytime maximum temperatures average around 24°C (75°F), whilst at night 12°C (54°F) is normal.

Portola Valley weather averages (imperial / metric)
Daytime temperature 23.6°C 74.5°F
Nightly temperature 12.2°C 54°F
Average temperature 17.9°C 64.2°F
Daily sunshine 10.4 hrs
Avg rainfall 2 mm 0.1 ins
Rainy days 1 days
Sea temperature 14°C 57.2°F
Humidity 71%
Windspeed 18.4kph 11 mph

On average August is the 2nd driest month of the year in Portola Valley with around 2mm 0.1 inches of rain making it a very dry time to visit.

On the flip side this corresponds to an average of 10.4 hours of sunshine per day.

August temperatures in Portola Valley

Portola Valley average temperature in August

August rainfall

Portola Valley average rain in August

August hourly sunshine

Portola Valley average rain in August

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 Portola Valley in August 2025.

Other monthly averages

Best places to visit in August

UV index Best time to go?

Beta

Current (hourly) weather 15 day forecast

Portola Valley weather stats

Portola Valley weather statistics
Hottest month: August 23.3°C 73.9°F
Driest month: July 2mm 0.1ins
Sunniest month: April 11.1hrs
Coldest month: January 13.3°C 55.9°F
Wettest month: January 133mm 5.2ins
Map showing location of Portola Valley (37.38411, -122.23524) Portola Valley map pin © Google

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