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Monthly
Precipitation
Temperature
Wind
Temperature Unit Selection
°Celsius
°Fahrenheit
Monthly Historical Averages
Castro Valley, CA
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August
Average Temperature
High
26°
Feels 26
Low
14°
Feels 13
Average Precipitation
0 Days
Rain amount
1.6mm
Snow amount
0cm
Content continues below
Daily Historical Averages
August 2026
S
M
T
W
T
F
S
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23°
23
24°
24
23°
25
22°
26
23°
27
23°
28
23°
29
24°
30
24°
31
23°
Forecast
Saturday, August 22, 2026
Day
23°
Feels 23
Wind
23 km/h SW
Gust
34 km/h
Humidity
46%
P.O.P
10%
Night
15°
Feels 15
Wind
20 km/h S
Gust
30 km/h
Humidity
85%
P.O.P
20%
Historical Averages
Aug 22
High
Feels
Low
Feels
Precip Frequency
Total Daylight
Humidity
Historical Averages are based on data recorded from 2000 onwards.