Clear Lake Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Clear Lake Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Clear Lake Reservoir today is 7.4°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
❌ As of today, the minimum water temperature ranges from 41°F (5°C) to 47°F (8°C). This water temperature is still quite low, and swimming in such conditions may only be comfortable for hardened individuals. It is recommended to limit the time spent in the water to avoid hypothermia. For those not accustomed to cold water, it is better to refrain from swimming. However, if you decide to enter the water, it is advisable to wear a warm wetsuit for protection against the cold. 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 |
|---|---|---|---|
| NOV 6 | 7.6°C | 6.4°C | |
| NOV 7 | 7.1°C | 6.4°C | |
| NOV 8 | 6.5°C | 6.4°C | |
| NOV 9 | 6.7°C | 6.4°C | |
| NOV 10 | 6.5°C | 6.4°C | |
| NOV 11 | 6.5°C | 6.4°C | |
| NOV 12 | 6.8°C | 6.4°C | |
| NOV 13 | 7.2°C | 6.4°C | |
| NOV 14 | 6.4°C | 7.4°C | |
| NOV 15 | 6.4°C | 7.3°C | |
| NOV 16 | 6.4°C | 7.3°C | |
| NOV 17 | 6.4°C | 7.2°C | |
| NOV 18 | 6.4°C | 7.2°C | |
| NOV 19 | 6.4°C | 7.1°C | |
| NOV 20 | 6.4°C | 7.1°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 | 0°C | 2°C | 4°C |
| February | 1°C | 4°C | 6°C |
| March | 0°C | 4°C | 9°C |
| April | 4°C | 8°C | 12°C |
| May | 12°C | 15°C | 19°C |
| June | 15°C | 18°C | 21°C |
| July | 17°C | 21°C | 26°C |
| August | 20°C | 22°C | 25°C |
| September | 16°C | 20°C | 23°C |
| October | 9°C | 14°C | 18°C |
| November | 2°C | 6°C | 10°C |
| December | 0°C | 3°C | 5°C |
Clear Lake Reservoir: Water Temperature by Location
Clear Lake Reservoir: Weather Forecast
November 14
November 15
November 16
November 17
November 18
November 19
Location & Local Information
Clear Lake in Lake County, California, typically shows noticeable seasonal swings in surface water temperature. In summer the surface often warms to roughly 70–85°F (21–29°C), with the warmest afternoons and shallow bays occasionally reaching the upper end of that range. Autumn sees cooling to about 60–75°F (15–24°C) as air temperatures drop and winds increase. Spring surface temperatures are commonly in the 50–65°F range (10–18°C) as the lake recovers from winter, while winter surface readings usually sit around 45–55°F (7–13°C). Temperatures below the surface can be appreciably colder, especially in deeper areas or after cold spells, and sudden changes can occur with weather or inflows.
Swimming in Clear Lake is generally permitted and many public parks and private accesses accommodate swimmers, but conditions vary and caution is advised. Recreational use is sometimes restricted because cyanobacterial (blue‑green algae) blooms occur periodically; when blooms are present health advisories may recommend avoiding skin contact or ingestion. Boat traffic, submerged vegetation and cooler subsurface temperatures also affect safety, and designated swim areas and posted signs are useful guides. It’s advisable to check current local water‑quality advisories, obey signage, and use common precautions such as not swimming alone and exiting the water if you notice visible algae or experience skin irritation.