Hourly Weather Forecast - Castro Valley, CA

12 AM
50°F
60%
13mph
SSE
60% Chance of Rain
Humidity
85%
Feels like
50°F
Dew Point
46°F
1 AM
50°F
60%
13mph
SSE
60% Chance of Rain
Humidity
86%
Feels like
50°F
Dew Point
46°F
2 AM
50°F
60%
14mph
SSE
60% Chance of Light Rain
Humidity
87%
Feels like
50°F
Dew Point
46°F
3 AM
50°F
60%
14mph
SSE
60% Chance of Light Rain
Humidity
88%
Feels like
50°F
Dew Point
47°F
4 AM
50°F
70%
15mph
SSE
70% Chance of Light Rain
Humidity
90%
Feels like
45°F
Dew Point
47°F
5 AM
50°F
80%
15mph
SSE
80% Chance of Light Rain
Humidity
90%
Feels like
44°F
Dew Point
47°F
6 AM
50°F
90%
15mph
SSE
Light Rain
Humidity
90%
Feels like
45°F
Dew Point
47°F
7 AM
50°F
90%
14mph
S
Light Rain
Humidity
90%
Feels like
50°F
Dew Point
47°F
7:21 AM
8 AM
50°F
90%
15mph
S
Light Rain
Humidity
90%
Feels like
50°F
Dew Point
47°F
9 AM
51°F
90%
15mph
S
Light Rain
Humidity
89%
Feels like
51°F
Dew Point
48°F
10 AM
52°F
90%
15mph
S
Light Rain
Humidity
86%
Feels like
52°F
Dew Point
48°F
11 AM
54°F
90%
15mph
S
Light Rain
Humidity
83%
Feels like
54°F
Dew Point
49°F
12 PM
55°F
90%
15mph
S
Light Rain
Humidity
80%
Feels like
55°F
Dew Point
49°F
1 PM
55°F
90%
15mph
S
Rain
Humidity
79%
Feels like
55°F
Dew Point
49°F
2 PM
55°F
80%
14mph
SSW
80% Chance of Rain
Humidity
79%
Feels like
55°F
Dew Point
48°F
3 PM
52°F
80%
13mph
SSW
80% Chance of Rain
Humidity
83%
Feels like
52°F
Dew Point
47°F
4 PM
49°F
80%
13mph
SSW
80% Chance of Rain
Humidity
86%
Feels like
44°F
Dew Point
45°F
4:55 PM
5 PM
47°F
70%
10mph
S
70% Chance of Light Rain
Humidity
92%
Feels like
42°F
Dew Point
44°F
6 PM
46°F
70%
10mph
S
70% Chance of Light Rain
Humidity
93%
Feels like
41°F
Dew Point
44°F
7 PM
46°F
70%
9mph
S
70% Chance of Light Rain
Humidity
92%
Feels like
41°F
Dew Point
44°F
8 PM
46°F
70%
9mph
S
70% Chance of Light Rain
Humidity
90%
Feels like
42°F
Dew Point
43°F
9 PM
46°F
80%
9mph
SSE
80% Chance of Light Rain
Humidity
90%
Feels like
42°F
Dew Point
43°F
10 PM
46°F
70%
9mph
SSE
70% Chance of Light Rain
Humidity
90%
Feels like
42°F
Dew Point
44°F
11 PM
46°F
70%
9mph
SSE
70% Chance of Light Rain
Humidity
90%
Feels like
42°F
Dew Point
44°F

Rain And Snow Totals Through Monday

Atmospheric River Takes Aim For Northern California

The plume of abundant moisture impacting the Northwest the last several days will focus more on Northern California later today into Monday bringing heavy rainfall and mountain snow.

NOAA, NCDC

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Weekend Weather Outlook

Weekend Weather Outlook

Cold weather

During Extreme Cold: Watch for Frostbite!

Flu Update Valid For Week Ending December 13, 2025

Weekly Flu Update: Flu Spreading Hard Across U.S.

Watch vs. Warning

Flash Flood Watch and Warning Defined

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