National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Strong Storm System Brings Heavy Mountain Snow to the Sierra Nevada and Critical Fire Weather Conditions to the Plains

A Pacific storm system will continue to bring low elevation rain and mountain snow to much of the West through Wednesday, with heavy mountain snow expected in the higher elevations of the Sierra Nevada. This system will also bring strong winds to the Intermountain West, Rockies, and Plains, which will create Critical fire weather conditions for the High Plains. Read More >

Current conditions at

Hayward, Hayward Air Terminal (KHWD)

Lat: 37.66083°NLon: 122.11833°WElev: 46.0ft.

Mostly Cloudy

56°F

13°C

Humidity 74%
Wind Speed W 4 MPH
Barometer 30.03 in (1016.93 mb)
Dewpoint 48°F (9°C)
Visibility 10.00 mi
Last update 21 Apr 08:54 PM PDT
Extended Forecast for

Castro Valley CA

  • Tonight

    Tonight: A chance of rain, mainly between 3am and 5am, then a chance of showers and thunderstorms after 5am. Mostly cloudy, with a low around 48. South wind around 7 mph. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 48 °F

    Mostly Cloudy
    then Chance
    Showers

  • Wednesday

    Wednesday: Rain and thunderstorms likely before 3pm, then a slight chance of rain between 3pm and 4pm. Partly sunny, with a high near 64. South southeast wind around 7 mph becoming west northwest in the afternoon. Chance of precipitation is 70%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 64 °F

    Showers
    Likely then
    Chance Rain

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 46. West northwest wind around 6 mph becoming calm in the evening.

    Low: 46 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 69. Calm wind becoming west 5 to 7 mph in the afternoon.

    High: 69 °F

    Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 49. Southwest wind 5 to 9 mph.

    Low: 49 °F

    Partly Cloudy

  • Friday

    Friday: Mostly cloudy, with a high near 66.

    High: 66 °F

    Mostly Cloudy

  • Friday Night

    Friday Night: Mostly cloudy, with a low around 50.

    Low: 50 °F

    Mostly Cloudy

  • Saturday

    Saturday: Partly sunny, with a high near 64.

    High: 64 °F

    Partly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 50.

    Low: 50 °F

    Partly Cloudy

Detailed Forecast

Tonight
A chance of rain, mainly between 3am and 5am, then a chance of showers and thunderstorms after 5am. Mostly cloudy, with a low around 48. South wind around 7 mph. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Wednesday
Rain and thunderstorms likely before 3pm, then a slight chance of rain between 3pm and 4pm. Partly sunny, with a high near 64. South southeast wind around 7 mph becoming west northwest in the afternoon. Chance of precipitation is 70%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Wednesday Night
Mostly clear, with a low around 46. West northwest wind around 6 mph becoming calm in the evening.
Thursday
Sunny, with a high near 69. Calm wind becoming west 5 to 7 mph in the afternoon.
Thursday Night
Partly cloudy, with a low around 49. Southwest wind 5 to 9 mph.
Friday
Mostly cloudy, with a high near 66.
Friday Night
Mostly cloudy, with a low around 50.
Saturday
Partly sunny, with a high near 64.
Saturday Night
Partly cloudy, with a low around 50.
Sunday
Mostly sunny, with a high near 65.
Sunday Night
Partly cloudy, with a low around 48.
Monday
Partly sunny, with a high near 67.
Monday Night
Mostly cloudy, with a low around 49.
Tuesday
Mostly sunny, with a high near 68.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Castro Valley CA
 37.72°N 122.05°W (Elev. 397 ft)
Last Update:
8:32 pm PDT Apr 21, 2026
Forecast Valid:
9pm PDT Apr 21, 2026-6pm PDT Apr 28, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation