Castaic Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Castaic Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Castaic Lake today is 19.6°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming. 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 |
|---|---|---|---|
| OCT 26 | 22.0°C | 23.9°C | |
| OCT 27 | 22.0°C | 23.9°C | |
| OCT 28 | 21.6°C | 23.9°C | |
| OCT 29 | 21.1°C | 23.9°C | |
| OCT 30 | 20.5°C | 23.9°C | |
| OCT 31 | 20.8°C | 23.9°C | |
| NOV 1 | 20.8°C | 20.5°C | |
| NOV 2 | 19.6°C | 20.5°C | |
| NOV 3 | 20.5°C | 19.6°C | |
| NOV 4 | 20.5°C | 19.7°C | |
| NOV 5 | 20.5°C | 19.7°C | |
| NOV 6 | 20.5°C | 19.8°C | |
| NOV 7 | 20.5°C | 19.8°C | |
| NOV 8 | 20.5°C | 19.9°C | |
| NOV 9 | 20.5°C | 19.9°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 | 11°C | 13°C | 16°C |
| February | 9°C | 12°C | 16°C |
| March | 8°C | 14°C | 20°C |
| April | 13°C | 17°C | 21°C |
| May | 18°C | 22°C | 26°C |
| June | 19°C | 23°C | 27°C |
| July | 22°C | 26°C | 30°C |
| August | 24°C | 28°C | 32°C |
| September | 22°C | 25°C | 29°C |
| October | 21°C | 24°C | 26°C |
| November | 16°C | 21°C | 24°C |
| December | 13°C | 17°C | 19°C |
Castaic Lake: Water Temperature by Location
Castaic Lake: Weather Forecast
November 3
November 4
November 5
November 6
November 7
Location & Local Information
Castaic Lake, a managed reservoir in Southern California, shows noticeable seasonal variation in surface water temperature. In winter the lake is cool, typically around 50–58°F (10–14°C). Spring sees a steady warming with surface temperatures often ranging from about 55–68°F (13–20°C) as air temperatures rise. During summer the shallow surface can warm considerably, commonly reaching roughly 68–78°F (20–26°C) on warm days, though deeper areas remain cooler. In autumn temperatures generally fall back into the 60–72°F (16–22°C) range as the lake begins to cool toward winter. These values are approximate and depend on recent weather, water levels and depth, but they highlight why the lake feels brisk outside the peak summer months.
Swimming is permitted only in designated areas and during times when lifeguards and park staff allow it; much of the reservoir is focused on boating, fishing and water storage so open swimming across the lake is discouraged or restricted for safety. Restrictions reflect hazards such as boat traffic, sudden depth changes, cold temperatures below the surface, and water-quality or reservoir-management concerns. If you plan to swim, use the designated swim zone when staffed, heed posted rules, and check current park advisories for closures or temperature-related cautions.