Climate and monthly weather forecastCastro Valley, CA
Climate and monthly weather forecast
Weather in January
January, the same as December, in Castro Valley, California, is a moderate winter month, with an average temperature varying between 43.7°F (6.5°C) and 57°F (13.9°C). January's weather records an average high-temperature of a still moderate 57°F (13.9°C), showing little deviation from December. Weather in January »Weather in February
February, the last month of the winter in Castro Valley, is another refreshing month, with an average temperature fluctuating between 59.5°F (15.3°C) and 44.1°F (6.7°C). February ushers in an average high-temperature of a still mild 59.5°F (15.3°C), aligning closely with the preceding month. Weather in February »Weather in March
The first month of the spring, March, is a comfortable month in Castro Valley, California, with temperature in the range of an average low of 45°F (7.2°C) and an average high of 61.9°F (16.6°C). The arrival of March brings an average high-temperature of an enjoyable 61.9°F (16.6°C), subtly diverging from February's 59.5°F (15.3°C). Weather in March »Weather in April
April, the same as March, is another comfortable spring month in Castro Valley, California, with an average temperature varying between 66.2°F (19°C) and 46.4°F (8°C). With the transition into April, Castro Valley notes an average high-temperature of a still enjoyable 66.2°F (19°C), closely resembling March. Weather in April »Weather in May
The last month of the spring, May, is an agreeable month in Castro Valley, California, with temperature in the range of an average low of 49.1°F (9.5°C) and an average high of 70.3°F (21.3°C). With the arrival of May, Castro Valley's average high-temperature registers at an agreeable 70.3°F (21.3°C), indicating a subtle variation from the previous month. Weather in May »Weather in June
June, the first month of the summer in Castro Valley, is a moderately hot month, with an average temperature fluctuating between 53.6°F (12°C) and 77°F (25°C). As May gives way to June, the average high-temperature displays a slight ascent, adjusting from a pleasant 70.3°F (21.3°C) to a moderately hot 77°F (25°C). Weather in June »Weather in July
July, like June, in Castro Valley, California, is a moderately hot summer month, with an average temperature ranging between min 55.2°F (12.9°C) and max 80.2°F (26.8°C). Castro Valley's temperatures tend to reach their peak averages in July, with a high of 80.2°F (26.8°C) and a low of 55.2°F (12.9°C). Weather in July »Weather in August
The last month of the summer, August, is another warm month in Castro Valley, California, with temperature in the range of an average low of 56.5°F (13.6°C) and an average high of 79.7°F (26.5°C). Stepping into August, Castro Valley records an average high-temperature of a still warm 79.7°F (26.5°C), almost consistent with July. Weather in August »Weather in September
September, the first month of the autumn in Castro Valley, is also a moderately hot month, with temperature in the range of an average high of 79°F (26.1°C) and an average low of 56.3°F (13.5°C). The average high-temperature during September registers at a still warm 79°F (26.1°C), closely corresponding to the preceding month. Weather in September »Weather in October
October, like September, is an agreeable autumn month in Castro Valley, California, with an average temperature varying between 72.5°F (22.5°C) and 54.3°F (12.4°C). Castro Valley's progression into October involves a gentle drop in the average high-temperature, from a warm 79°F (26.1°C) in September to an agreeable 72.5°F (22.5°C). Weather in October »Weather in November
November, the last month of the autumn in Castro Valley, is another refreshing month, with an average temperature fluctuating between 63.5°F (17.5°C) and 48.2°F (9°C). November involves a decrease in temperature, down from a pleasant 72.5°F (22.5°C) in October to a comfortable 63.5°F (17.5°C). Weather in November »Weather in December
The first month of the winter, December, is also a moderate month in Castro Valley, California, with an average temperature fluctuating between 43.7°F (6.5°C) and 55.9°F (13.3°C). The lowest temperatures are recorded in December, with averages reaching a high of 55.9°F (13.3°C) and a low of 43.7°F (6.5°C). Weather in December »Updated: Feb 9, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Throughout the year, in Castro Valley, there are 69.2 rainfall days, and 11.1" (282mm) of precipitation is accumulated.
January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index in Castro Valley, California.
The month with the most rainfall in Castro Valley, California, is February, when the rain falls for 8.3 days and typically aggregates up to 2.28" (58mm) of precipitation.
March is the most humid month, with an average relative humidity of 74%.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Castro Valley, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.
June has the longest days of the year in Castro Valley, with an average of 14h and 42min of daylight.
With an average maximum UV index of 6, June is the month with the highest UV index in Castro Valley.
July, with its average high-temperature of 80.2°F (26.8°C) and an average low-temperature of 55.2°F (12.9°C), holds the record as the warmest month in Castro Valley.
The months with the least rainfall are July and August Rain falls for 1.5 days and accumulates 0.04" (1mm) of rain.
The month with the most sunshine in Castro Valley, California, is July, with an average of 12.1h of sunshine.
September is the least humid month, with an average relative humidity of 61%.
The lowest temperatures in Castro Valley, California, are recorded in December, with averages reaching a high of 55.9°F (13.3°C) and a low of 43.7°F (6.5°C).
The month with the shortest days is December, with an average of 9h and 36min of daylight.
December has the least sunshine of the year in Castro Valley, California, with an average of 5.9h of sunshine.
Average temperature
Castro Valley, CA
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is December (55.9°F).
The month with the highest average low temperature is August (56.5°F).
The coldest months (with the lowest average low temperature) are January and December (43.7°F).
Average pressure
Castro Valley, CA
- Average pressure in January:
30.14"Hg - Average pressure in February:
30.08"Hg - Average pressure in March:
30.07"Hg - Average pressure in April:
30.03"Hg - Average pressure in May:
29.98"Hg - Average pressure in June:
29.92"Hg
- Average pressure in July:
29.93"Hg - Average pressure in August:
29.92"Hg - Average pressure in September:
29.92"Hg - Average pressure in October:
29.98"Hg - Average pressure in November:
30.07"Hg - Average pressure in December:
30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed
Castro Valley, CA
- Average wind speed in January:
4.8mph - Average wind speed in February:
5.8mph - Average wind speed in March:
6mph - Average wind speed in April:
6.3mph - Average wind speed in May:
6.6mph - Average wind speed in June:
6.3mph
- Average wind speed in July:
5.7mph - Average wind speed in August:
5.4mph - Average wind speed in September:
5mph - Average wind speed in October:
4.7mph - Average wind speed in November:
4.6mph - Average wind speed in December:
5.2mph
The windiest month (with the highest average wind speed) is May (6.6mph).
The calmest month (with the lowest average wind speed) is November (4.6mph).
Average humidity
Castro Valley, CA
The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is September (61%).
Average rainfall
Castro Valley, CA
- Average rainfall in January:
1.89" - Average rainfall in February:
2.28" - Average rainfall in March:
1.81" - Average rainfall in April:
0.63" - Average rainfall in May:
0.51" - Average rainfall in June:
0.12"
- Average rainfall in July:
0.04" - Average rainfall in August:
0.04" - Average rainfall in September:
0.12" - Average rainfall in October:
0.51" - Average rainfall in November:
1.34" - Average rainfall in December:
1.81"
The wettest month (with the highest rainfall) is February (2.28").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days
Castro Valley, CA
- Average rainfall days in January:
9.3 days - Average rainfall days in February:
8.3 days - Average rainfall days in March:
12.4 days - Average rainfall days in April:
7 days - Average rainfall days in May:
4.3 days - Average rainfall days in June:
1.6 days
- Average rainfall days in July:
1.5 days - Average rainfall days in August:
0.9 days - Average rainfall days in September:
2.1 days - Average rainfall days in October:
4.6 days - Average rainfall days in November:
7 days - Average rainfall days in December:
10.2 days
The month with the highest number of rainy days is March (12.4 days).
The month with the least rainy days is August (0.9 days).
Average daylight / Average sunshine
Castro Valley, CA
- Average daylight in January:
9h and 54min - Average daylight in February:
10h and 48min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 12min - Average daylight in May:
14h and 12min - Average daylight in June:
14h and 42min
- Average daylight in July:
14h and 30min - Average daylight in August:
13h and 36min - Average daylight in September:
12h and 24min - Average daylight in October:
11h and 12min - Average daylight in November:
10h and 6min - Average daylight in December:
9h and 36min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in January:
6h and 18min - Average sunshine in February:
6h and 18min - Average sunshine in March:
8h and 0min - Average sunshine in April:
10h and 30min - Average sunshine in May:
10h and 54min - Average sunshine in June:
11h and 48min
- Average sunshine in July:
12h and 6min - Average sunshine in August:
12h and 0min - Average sunshine in September:
11h and 6min - Average sunshine in October:
7h and 6min - Average sunshine in November:
6h and 36min - Average sunshine in December:
5h and 54min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days
Castro Valley, CA
- Average sunshine days in January:
20.5 days - Average sunshine days in February:
18.8 days - Average sunshine days in March:
17.3 days - Average sunshine days in April:
22.1 days - Average sunshine days in May:
26 days - Average sunshine days in June:
27.3 days
- Average sunshine days in July:
28.8 days - Average sunshine days in August:
28.9 days - Average sunshine days in September:
27.1 days - Average sunshine days in October:
25.5 days - Average sunshine days in November:
22.4 days - Average sunshine days in December:
19.4 days
The month with the most sunshine days is August (28.9 days).
The month with the least sunshine days is March (17.3 days).
Average UV index
Castro Valley, CA
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover
Castro Valley, CA
The months with the most cloud cover are March and December (Cloud cover 34).
The month with the least cloud cover is July (Cloud cover 7).
Average visibility
Castro Valley, CA
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
