Lake Washington — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Washington, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Washington 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 |
|---|---|---|---|
| SEP 14 | 20.1°C | 20.0°C | |
| SEP 15 | 20.1°C | 20.0°C | |
| SEP 16 | 19.9°C | 20.0°C | |
| SEP 17 | 19.2°C | 20.0°C | |
| SEP 18 | 18.1°C | 20.0°C | |
| SEP 19 | 18.5°C | 20.0°C | |
| SEP 20 | 18.7°C | 20.0°C | |
| SEP 21 | 19.6°C | 20.0°C | |
| SEP 22 | 20.0°C | 19.6°C | |
| SEP 23 | 20.0°C | 19.6°C | |
| SEP 24 | 20.0°C | 19.7°C | |
| SEP 25 | 20.0°C | 19.7°C | |
| SEP 26 | 20.0°C | 19.7°C | |
| SEP 27 | 20.0°C | 19.7°C | |
| SEP 28 | 20.0°C | 19.7°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 | 7°C | 12°C |
| February | 0°C | 8°C | 15°C |
| March | 0°C | 9°C | 17°C |
| April | 1°C | 11°C | 20°C |
| May | 10°C | 17°C | 24°C |
| June | 15°C | 19°C | 24°C |
| July | 17°C | 23°C | 30°C |
| August | 20°C | 24°C | 28°C |
| September | 18°C | 20°C | 22°C |
| October | 5°C | 12°C | 19°C |
| November | 4°C | 8°C | 11°C |
| December | 0°C | 4°C | 8°C |
Lake Washington: Water Temperature by Location
Lake Washington: Weather Forecast
September 22
September 23
September 24
September 25
Location & Local Information
Lake Washington in Minnesota follows the seasonal pattern of many midwestern glacial lakes. After ice-out in spring, surface waters typically warm from about 40–60°F (4–16°C) through late spring. Summer surface temperatures commonly range from roughly 68–78°F (20–26°C), and during heat waves can briefly reach the low 80s°F (around 27–28°C). By early fall the surface cools back into the mid-40s to low 60s°F (7–17°C) as the lake destratifies, and in winter the water sits near 32°F (0°C) under ice. Deeper water remains colder year-round, often several degrees cooler than the surface during summer due to thermal stratification.
Swimming in Lake Washington is generally permitted and popular in warm months where public access, beaches, or private properties provide safe entry points. Local authorities may post advisories when harmful algal blooms, elevated bacteria counts, or unsafe conditions occur, and water visibility and temperature can affect safety; cold shock is a risk in spring and late fall. Ice and closed-season regulations make winter swimming uncommon except for organized events or ice-fishing holes cleared for brief dips. Visitors should check current local conditions, follow posted guidance, and be mindful of depth, currents, and sudden temperature changes before swimming.