Rock Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Rock Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Rock Lake today is 18.9°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 |
|---|---|---|---|
| JUN 23 | 20.2°C | 17.5°C | |
| JUN 24 | 20.6°C | 17.5°C | |
| JUN 25 | 20.7°C | 17.5°C | |
| JUN 26 | 20.7°C | 17.5°C | |
| JUN 27 | 19.2°C | 17.5°C | |
| JUN 28 | 19.1°C | 17.5°C | |
| JUN 29 | 19.0°C | 17.5°C | |
| JUN 30 | 18.9°C | 17.5°C | |
| JUL 1 | 21.7°C | 19.0°C | |
| JUL 2 | 21.7°C | 19.2°C | |
| JUL 3 | 21.7°C | 19.3°C | |
| JUL 4 | 21.7°C | 19.5°C | |
| JUL 5 | 21.7°C | 19.6°C | |
| JUL 6 | 21.7°C | 19.7°C | |
| JUL 7 | 21.7°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 | 0°C | 1°C | 4°C |
| February | 0°C | 2°C | 5°C |
| March | 0°C | 4°C | 7°C |
| April | 3°C | 8°C | 14°C |
| May | 7°C | 13°C | 20°C |
| June | 14°C | 18°C | 21°C |
| July | 19°C | 22°C | 24°C |
| August | 21°C | 23°C | 26°C |
| September | 16°C | 20°C | 24°C |
| October | 10°C | 15°C | 19°C |
| November | 4°C | 8°C | 11°C |
| December | 1°C | 4°C | 7°C |
Rock Lake: Water Temperature by Location
Rock Lake: Weather Forecast
July 1
July 2
July 3
July 4
Location & Local Information
Rock Lake in Washington typically follows the seasonal temperature patterns of other small inland lakes in the region. Surface temperatures in winter often hover just above freezing, roughly 33–40°F (1–4°C), while spring brings a steady rise into the 40–60°F range (4–16°C) as the lake mixes and the upper layers warm. Peak warmth usually occurs in late summer, with surface readings commonly between 60–75°F (15–24°C) on sunny, calm days; deeper water remains significantly cooler. By fall the surface begins to cool again, generally falling to about 50–65°F (10–18°C) as the lake returns toward winter stratification. Exact temperatures vary year to year with weather, runoff and lake depth.
Swimming at Rock Lake is generally possible and is a common recreational use where public access and beaches exist, but whether it is officially allowed depends on local rules and posted signs. Water quality, boat traffic, and safety conditions such as cold-water shock or sudden depth changes influence whether people choose to swim; lifeguards are rarely present at smaller lakes, so swimmers should exercise caution. In summer, when surface temperatures are highest, swimming is most comfortable, whereas spring and fall waters can feel very chilly and increase the risk of hypothermia. Always check local advisories and obey any posted restrictions before entering the water.