Lake McDonald — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake McDonald, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake McDonald today is 21.6°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 |
|---|---|---|---|
| AUG 4 | 21.7°C | 21.0°C | |
| AUG 5 | 21.7°C | 21.0°C | |
| AUG 6 | 21.4°C | 21.0°C | |
| AUG 7 | 21.4°C | 21.0°C | |
| AUG 8 | 21.2°C | 21.0°C | |
| AUG 9 | 21.2°C | 21.0°C | |
| AUG 10 | 21.6°C | 21.0°C | |
| AUG 11 | 21.6°C | 21.0°C | |
| AUG 12 | 21.0°C | 21.6°C | |
| AUG 13 | 21.0°C | 21.5°C | |
| AUG 14 | 21.0°C | 21.5°C | |
| AUG 15 | 21.0°C | 21.5°C | |
| AUG 16 | 21.0°C | 21.5°C | |
| AUG 17 | 21.0°C | 21.4°C | |
| AUG 18 | 21.0°C | 21.4°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 | 5°C |
| February | 0°C | 3°C | 5°C |
| March | 1°C | 3°C | 6°C |
| April | 1°C | 4°C | 7°C |
| May | 3°C | 9°C | 15°C |
| June | 10°C | 14°C | 18°C |
| July | 14°C | 18°C | 23°C |
| August | 17°C | 21°C | 25°C |
| September | 14°C | 17°C | 20°C |
| October | 6°C | 11°C | 15°C |
| November | 3°C | 6°C | 9°C |
| December | 0°C | 2°C | 5°C |
Lake McDonald: Water Temperature by Location
Lake McDonald: Weather Forecast
August 12
August 13
August 14
August 15
Location & Local Information
Lake McDonald is fed by snowmelt and mountain streams, so its surface temperatures stay quite cool through the year. In spring (April–June) the lake typically runs from near freezing up to roughly 32–45°F (0–7°C) as ice melts and runoff remains cold. Summer highs in July and August can warm surface water to about 50–65°F (10–18°C) on sunny afternoons, though deeper water remains much colder and winds can lower temperatures quickly. By fall the surface cools back into the mid-30s to low-50s °F (2–10°C) range as air temperatures drop, and in winter the lake is often near freezing or partially ice-covered with surface temperatures around 32°F (0°C) or below.
Swimming is allowed in Glacier National Park but is limited by practical safety concerns rather than strict prohibition. Short swims and quick wading are common in summer, yet the cold water raises a real risk of cold shock and hypothermia even on warm days, so prolonged immersion is dangerous. There are no lifeguards at Lake McDonald, boat traffic and shifting weather can increase hazards, and visitors are advised to exercise caution, wear protective clothing or wetsuits for longer exposure, and avoid swimming alone.