Portola Valley Weather in October

The climate in Portola Valley during October can be summarized as mild and reasonably dry.

October is in the fall / autumn in Portola Valley and is typically the 5th warmest month of the year. Daytime maximum temperatures average around 22°C (71°F), whilst at night 10°C (50°F) is normal.

On average October is the 6th driest month of the year in Portola Valley with around 35mm 1.4 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 4 days, although this may vary considerably.

On the flip side this corresponds to an average of 8.9 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 Portola Valley in October 2025.