Castro Valley water temp
This data the coastal Castro Valley ocean water temperature today, tomorrow and the upcoming days. Besides, you can also get information about the weather and surf forecast, as well as the data on sunrise / sunset and moonrise / moonset at a given point on any given day.
Current ocean temperature in Castro Valley
Water temperature in Castro Valley today is 70.9°F. Based on our historical data over a period of ten years, the warmest water in this day in Castro Valley was recorded in 2022 and was 73.2°F, and the coldest was recorded in 2012 at 56.7°F. Sea water temperature in Castro Valley is expected to drop to 62.6°F in the next 10 days. September average water temperature in Castro Valley is 62.4°F, the minimum temperature is 55.6°F, and the maximum is 75.4°F.
The swimming season in Castro Valley lasts from June to September. During those months, Castro Valley water temperature does not drop below 68°F and therefore suitable for comfortable swimming. The average water temperature in Castro Valley in winter reaches 53.2°F, in spring 56.5°F, in summer the average temperature rises to 61.5°F, and in autumn it is 60.3°F.
Castro Valley water temperature now
| September 5, 2025 |
|---|
| today temp |
| 70.9°F |
| September 4, 2025 |
|---|
| yesterday temp |
| 72°F |
The ocean salinity in Castro Valley is 11.23‰, and the average salinity of the World Ocean is 35‰.
Surf Forecast in Castro Valley for today
Another important indicators for a comfortable holiday on the beach are the presence and height of the waves, as well as the speed and direction of the wind. Please find below data on the swell size for Castro Valley. We calculate the swell size based on the mean wave height (trough to crest) of each third highest wave. For more information on surf forecasts for the next ten days, please visit sea state forecast Castro Valley. Data in table shown for September 5, 2025, time in GMT 0 format (you can change the time zone on the sea state forecast page)
| 0-3 h | 3-6 h | 6-9 h | 9-12 h |
|---|---|---|---|
| 1' 3" | 1' 1" | 1' 1" | 1' 1" |
| 0.38 m | 0.34 m | 0.33 m | 0.33 m |
| 12-15 h | 15-18 h | 18-21 h | 21-24 h |
|---|---|---|---|
| 1' 0" | 1' 1" | 1' 2" | 1' 4" |
| 0.31 m | 0.34 m | 0.36 m | 0.4 m |
Surf report in Castro Valley
Castro Valley weather forecast
Current temperature and weather
Data in a table show Castro Valley temperature today (September 5, 2025). For more information and forecast for a few days, go to the weather forecast Castro Valley.
| 0-3 h | 3-6 h | 6-9 h | 9-12 h |
|---|---|---|---|
 | | | |
| 62.4°F | 61.5°F | 61.2°F | 61.7°F |
| 12-15 h | 15-18 h | 18-21 h | 21-24 h |
|---|---|---|---|
| | | |
| 63.9°F | 65.1°F | 63°F | 60.6°F |
You may also be interested in other sections of our site for Castro Valley: Sunrise and Sunset, Tides
Castro Valley water temperature by month
These figures shows the average, minimum and maximum monthly sea temperature in Castro Valley. In addition to the table values, the graph below displays of changes average surface temperature during the year. Values are calculated based on the data over the past 10 years. Using them, you can check the water temperature in Castro Valley on any day of this period that interests you. Click on the month link and you will see a table for each day, or alternatively you can view the temperature curve of the month and select 2 different years you want to compare, either in a table or as a curve
| Month | Avr | Min | Max | |
|---|---|---|---|---|
| January | 52.3°F | 50°F | 56.1°F | cold |
| Ocean water temperature in Castro Valley in January | ||||
| February | 53.4°F | 50.4°F | 59.5°F | cold |
| Ocean water temperature in Castro Valley in February | ||||
| March | 55.2°F | 49.1°F | 60.6°F | cold |
| Ocean water temperature in Castro Valley in March | ||||
| April | 56.7°F | 50.7°F | 66.4°F | cold |
| Ocean water temperature in Castro Valley in April | ||||
| May | 57.6°F | 50°F | 70.9°F | cold |
| Ocean water temperature in Castro Valley in May | ||||
| June | 60.1°F | 51.8°F | 74.5°F | cold |
| Ocean water temperature in Castro Valley in June | ||||
| July | 62.1°F | 52.9°F | 75.2°F | cold |
| Ocean water temperature in Castro Valley in July | ||||
| August | 62.6°F | 54.1°F | 75.4°F | cold |
| Ocean water temperature in Castro Valley in August | ||||
| September | 62.4°F | 55.6°F | 75.4°F | cold |
| Ocean water temperature in Castro Valley in September | ||||
| October | 60.8°F | 54.3°F | 72.5°F | cold |
| Ocean water temperature in Castro Valley in October | ||||
| November | 57.7°F | 52.5°F | 64.4°F | cold |
| Ocean water temperature in Castro Valley in November | ||||
| December | 54.1°F | 50.4°F | 59.2°F | cold |
| Ocean water temperature in Castro Valley in December | ||||
Chart monthly average water temperature in Castro Valley
