Annual mean 15°C · wettest around March · prevailing wind NW
Warmest
24.2 °C
Coldest
12.3 °C
Wettest
27%
Windiest
5.3 m/s
Prevailing
NW
4.1 m/s average
When this place is good five ratings · thirty-six ten-day sections · click a cell to read it
never good
never good
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Every reading
bars actual · line feels-like, °Cchance of rain, %wind speed, m/ssky covered, %
The average temperature in Castro Valley over the whole year is 15°C. August is the hottest month, with highs of about 24°C; February is the coldest, with lows of about 8°C. The rainy (wet) season in Castro Valley runs from November to April, peaking in March with a 29% chance of rain on a given day. The dry season is May to October; June is the driest month, at 6%. Winds in Castro Valley are highest in June, averaging 4.3 m/s (15 km/h), and lightest in November, at 2.1 m/s (8 km/h). The prevailing wind is from the NW. The clearest skies in Castro Valley come in June, when the sky is typically 22% covered; January is the cloudiest month, at 47%.
Month by month Castro Valley climate by month: average temperatures year round · click a month to read it
Month
High
Low
Feels like
Chance of rain
Cloud
Wind
Being outside
Sun
Walking
January
13°C
8°C
10°C
28%
47%
2.5 m/s
13
0
79
February
14°C
8°C
11°C
27%
34%
2.9 m/s
24
0
77
March
15°C
9°C
12°C
29%
44%
3.2 m/s
29
0
81
April
18°C
11°C
15°C
20%
33%
3.6 m/s
53
4
84
May
20°C
13°C
17°C
16%
33%
4.1 m/s
65
10
79
June
23°C
15°C
20°C
6%
22%
4.3 m/s
73
23
64
July
23°C
15°C
21°C
8%
24%
4.3 m/s
77
30
58
August
24°C
16°C
22°C
8%
26%
3.9 m/s
79
34
54
September
23°C
15°C
22°C
9%
25%
3.3 m/s
78
28
59
October
21°C
13°C
19°C
16%
24%
2.6 m/s
78
15
74
November
16°C
9°C
14°C
21%
32%
2.1 m/s
44
1
88
December
13°C
8°C
11°C
27%
42%
2.2 m/s
13
0
79
High and low are the warmest and coolest of four readings a day — midnight, 6am, noon and 6pm — so a true overnight low can sit a degree or two under them. Chance of rain, cloud and wind are the day’s average; feels-like and the three ratings (each out of 100: Good from 55, Ideal from 80) are read at midday.
Seasons, and the year in short Castro Valley weather by season
Year round, Castro Valley has days of about 13°C at their warmest in December, its coolest month, and 24°C in August, its warmest; the coolest hours of the day run from 8°C to 16°C through the year, and the average temperature over the year is 15°C around the clock. Rain is most likely around March and least likely around June. Every figure here is a decade of observations blended into one representative year, so it reads as what this date is usually like, not a forecast for one particular day.
Castro Valley weather in winterDecember to February
High 13°CLow 8°CRain 27%
Winter in Castro Valley has typical daily highs of about 13°C and lows of about 8°C, with a 27% chance of rain on a given day.
Castro Valley weather in springMarch to May
High 18°CLow 11°CRain 22%
Spring in Castro Valley has typical daily highs of about 18°C and lows of about 11°C, with a 22% chance of rain on a given day.
Castro Valley weather in summerJune to August
High 23°CLow 15°CRain 7%
Summer in Castro Valley has typical daily highs of about 23°C and lows of about 15°C, with a 7% chance of rain on a given day.
Castro Valley weather in autumnSeptember to November
High 20°CLow 13°CRain 15%
Autumn in Castro Valley has typical daily highs of about 20°C and lows of about 13°C, with a 15% chance of rain on a given day.
When is the rainy season in Castro Valley?
The rainy (wet) season in Castro Valley runs from November to April, peaking in March with a 29% chance of rain on a given day. The dry season is May to October; June is the driest month, at 6%.
What time of year is Castro Valley windiest?
Winds in Castro Valley are highest in June, averaging 4.3 m/s (15 km/h), and lightest in November, at 2.1 m/s (8 km/h). The prevailing wind is from the NW.
What is the average temperature in Castro Valley year round?
The average temperature in Castro Valley over the whole year is 15°C. August is the hottest month, with highs of about 24°C; February is the coldest, with lows of about 8°C.