Castac Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Castac Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Castac Lake today is 20.8°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 68°F (20°C) to 74°F (23°C). The water is warm and pleasant for swimming, and in this range, one can stay in the water for extended periods without the risk of hypothermia. This is the ideal temperature for relaxation, swimming, and water sports. Families with children, as well as outdoor enthusiasts, will enjoy swimming and time spent in the water. For most people, this is the optimal temperature for a comfortable beach experience. It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.
Water Temperature Chart Over the Last 30 Days
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| JUN 3 | 20.2°C | 23.9°C | |
| JUN 4 | 20.2°C | 23.9°C | |
| JUN 5 | 20.3°C | 23.9°C | |
| JUN 6 | 20.4°C | 23.9°C | |
| JUN 7 | 21.0°C | 23.9°C | |
| JUN 8 | 21.0°C | 23.9°C | |
| JUN 10 | 20.8°C | 23.9°C | |
| JUN 11 | 23.9°C | 21.0°C | |
| JUN 12 | 23.9°C | 21.1°C | |
| JUN 13 | 23.9°C | 21.3°C | |
| JUN 14 | 23.9°C | 21.4°C | |
| JUN 15 | 23.9°C | 21.6°C | |
| JUN 16 | 23.9°C | 21.7°C | |
| JUN 17 | 23.9°C | 21.9°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 5°C | 8°C | 10°C |
| February | 4°C | 8°C | 12°C |
| March | 8°C | 12°C | 16°C |
| April | 13°C | 19°C | 24°C |
| May | 16°C | 21°C | 26°C |
| June | 18°C | 24°C | 29°C |
| July | 25°C | 30°C | 35°C |
| August | 26°C | 31°C | 35°C |
| September | 25°C | 30°C | 35°C |
| October | 22°C | 31°C | 39°C |
| November | 12°C | 22°C | 32°C |
| December | 9°C | 13°C | 16°C |
Castac Lake: Water Temperature by Location
Castac Lake: Weather Forecast
June 9
June 10
June 11
June 12
Location & Local Information
Castac Lake is a relatively shallow, seasonal-feeding lake in southern California, so its water temperature swings with air temperature and sunlight. Typical seasonal ranges run roughly 40–55°F (4–13°C) in winter, 50–65°F (10–18°C) in spring, 65–78°F (18–26°C) in summer, and 55–70°F (13–21°C) in fall. Because the lake is not very deep, it can warm quickly on hot summer days but also cool rapidly during cool spells and at night. These numbers are approximate and will vary year to year with precipitation and weather patterns.
Swimming opportunities at Castac Lake are limited and often discouraged. Much of the shoreline is privately owned and there are no widely maintained public swim beaches or lifeguard services, so legal access can be restricted. In addition, shallow inland lakes in the region can experience water quality issues such as elevated bacteria or harmful algal blooms in warm months, which present health risks for swimmers. For those considering entering the water, it’s best to check local rules and recent water-quality advisories and to avoid swimming where access is private or where advisories are posted.