Hourly Weather Forecast - Castro Valley, CA

2 AM
56°F
70%
6mph
S
70% Chance of Light Rain
Humidity
94%
Feels like
56°F
Dew Point
55°F
3 AM
56°F
70%
6mph
S
70% Chance of Light Rain
Humidity
94%
Feels like
56°F
Dew Point
55°F
4 AM
56°F
50%
5mph
S
50% Chance of Light Rain
Humidity
96%
Feels like
56°F
Dew Point
55°F
5 AM
56°F
30%
5mph
S
30% Chance of Light Rain
Humidity
96%
Feels like
56°F
Dew Point
55°F
6 AM
56°F
30%
5mph
S
30% Chance of Light Rain
Humidity
97%
Feels like
56°F
Dew Point
55°F
7 AM
56°F
30%
5mph
S
30% Chance of Light Rain
Humidity
98%
Feels like
56°F
Dew Point
56°F
7:19 AM
8 AM
56°F
30%
5mph
S
30% Chance of Light Rain
Humidity
99%
Feels like
56°F
Dew Point
56°F
9 AM
57°F
30%
5mph
SSW
30% Chance of Light Rain
Humidity
100%
Feels like
57°F
Dew Point
57°F
10 AM
58°F
20%
5mph
SW
Cloudy
Humidity
98%
Feels like
58°F
Dew Point
57°F
11 AM
59°F
30%
5mph
SSW
30% Chance of Light Rain
Humidity
95%
Feels like
59°F
Dew Point
58°F
12 PM
61°F
30%
5mph
SW
30% Chance of Light Rain
Humidity
91%
Feels like
61°F
Dew Point
58°F
1 PM
61°F
40%
5mph
SW
40% Chance of Light Rain
Humidity
91%
Feels like
61°F
Dew Point
58°F
2 PM
59°F
40%
5mph
SW
40% Chance of Light Rain
Humidity
94%
Feels like
59°F
Dew Point
58°F
3 PM
58°F
30%
5mph
S
30% Chance of Light Rain
Humidity
97%
Feels like
58°F
Dew Point
57°F
4 PM
57°F
40%
5mph
S
40% Chance of Light Rain
Humidity
96%
Feels like
57°F
Dew Point
55°F
4:52 PM
5 PM
56°F
60%
5mph
S
60% Chance of Light Rain
Humidity
92%
Feels like
56°F
Dew Point
54°F
6 PM
56°F
60%
5mph
SSE
60% Chance of Light Rain
Humidity
90%
Feels like
56°F
Dew Point
53°F
7 PM
56°F
80%
6mph
S
80% Chance of Light Rain
Humidity
90%
Feels like
56°F
Dew Point
53°F
8 PM
56°F
80%
6mph
S
80% Chance of Light Rain
Humidity
91%
Feels like
56°F
Dew Point
54°F
9 PM
56°F
80%
8mph
S
80% Chance of Light Rain
Humidity
91%
Feels like
56°F
Dew Point
54°F
10 PM
56°F
70%
8mph
S
70% Chance of Light Rain
Humidity
93%
Feels like
56°F
Dew Point
54°F
11 PM
56°F
60%
9mph
SSW
60% Chance of Light Rain
Humidity
94%
Feels like
56°F
Dew Point
55°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

White Christmas? What Are The Odds

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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