ClimateForecastNovemberDecember >>

Castro Valley (CA) Climate by Month

Temperatures see a moderate degree of fluctuation, transitioning from warm conditions to mild. It receives mid-range precipitation levels. Let’s explore the climate details in depth to provide you with a complete overview.

Average day and night temperature

The weather in Castro Valley changes moderately throughout the year, offering enough variation to appreciate each season. Average daytime temperatures range from a comfortable 25°C in September, the warmest time of the year, to a moderate 14°C during cooler months like December. At night, temperatures typically average around 5°C during these months.

The mean minimum and maximum temperatures throughout the year

Precipitation and rainy days

Generally, Castro Valley experiences moderate precipitation patterns, averaging 512 mm yearly. Significant seasonal changes in precipitation occur throughout the year. During the wetter season, December receives high rainfall, averaging 111 mm of precipitation, recorded across 13 rainy days. In contrast, the drier season, August brings less rainfall, with 0.1 mm over 0 rainy days.

The mean monthly precipitation over the year, including rain, hail and snow

Sunshine over the year

Seasonal changes in sunshine hours are quite dramatic in Castro Valley. While May receives considerable daily sunshine with up to 10.8 hours, December marks the darkest time of the year, where sunshine is scarce with only 5.3 hours of sunlight per day.

Monthly hours of sunshine

Data from: San Francisco, the United States of America (27 KM, 17 Miles).

Daily hours of sunshine

Data from: San Francisco, the United States of America (27 KM, 17 Miles).

The best time of year to visit Castro Valley in the United States of America

During the months of May, June, July, August, September and October you are most likely to experience good weather with pleasant average temperatures that fall between 20°C and 26°C.

Other facts from our historical weather data:
  • Does Castro Valley have a dry season?
    Yes, the months of May, June, July, August and September are very dry.
  • Which is the warmest month in Castro Valley?
    September has an average maximum temperature of 25°C and is the warmest month of the year.
  • Which is the coldest month in Castro Valley?
    The coldest month is December with an average maximum temperature of 14°C.
  • Which is the wettest month in Castro Valley?
    December tops the wettest month list with 111 mm of rainfall.
  • Which is the driest month in Castro Valley?
    August is the driest month with 0 mm of precipitation.
  • Which is the sunniest month in Castro Valley?
    May is the sunniest month with an average of 324 hours of sunshine.

  • No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.

    Forecast for Castro Valley (CA)

    Sat   Nov 23
    18°C | 10°C
    SW 14 km/h
    2.8 mm
    partly cloudy and  chance of rain

    partly cloudy and chance of rain

    Sun   Nov 24
    18°C | 9°C
    S 14 km/h
    5.6 mm
    partly cloudy and rain

    partly cloudy and rain

    Mon   Nov 25
    16°C | 11°C
    N 11 km/h
    9.2 mm
    overcast and heavy rain

    overcast and heavy rain