Lake Rosseau — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Rosseau, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Rosseau today is 18.1°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 | 19.8°C | 21.0°C | |
| SEP 15 | 19.6°C | 21.0°C | |
| SEP 16 | 19.8°C | 21.0°C | |
| SEP 17 | 19.2°C | 21.0°C | |
| SEP 18 | 19.4°C | 21.0°C | |
| SEP 19 | 19.3°C | 21.0°C | |
| SEP 20 | 18.8°C | 21.0°C | |
| SEP 21 | 18.1°C | 21.0°C | |
| SEP 22 | 21.0°C | 18.2°C | |
| SEP 23 | 21.0°C | 18.4°C | |
| SEP 24 | 21.0°C | 18.5°C | |
| SEP 25 | 21.0°C | 18.7°C | |
| SEP 26 | 21.0°C | 18.8°C | |
| SEP 27 | 21.0°C | 19.0°C | |
| SEP 28 | 21.0°C | 19.1°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 | 3°C | 6°C |
| February | 0°C | 4°C | 7°C |
| March | 0°C | 3°C | 6°C |
| April | 0°C | 7°C | 14°C |
| May | 3°C | 13°C | 22°C |
| June | 10°C | 17°C | 24°C |
| July | 16°C | 22°C | 27°C |
| August | 18°C | 24°C | 29°C |
| September | 17°C | 21°C | 25°C |
| October | 13°C | 16°C | 18°C |
| November | 3°C | 9°C | 13°C |
| December | 1°C | 5°C | 8°C |
Lake Rosseau: Water Temperature by Location
Lake Rosseau: Weather Forecast
September 21
September 22
September 23
September 24
September 25
September 26
Location & Local Information
Lake Rosseau, located in Ontario’s Muskoka region, is one of the province’s most famous and picturesque lakes, known for its deep, clear water and scenic granite shores. Because of its size and depth, the water temperature in Lake Rosseau varies greatly by season. During winter, the lake freezes partially, and surface temperatures hover near 0 °C (32 °F). In spring, as the ice melts, the water remains cold, typically between 5–10 °C (41–50 °F). By midsummer, the surface warms to about 19–24 °C (66–75 °F), while deeper layers stay much cooler, often below 12 °C (54 °F). In autumn, temperatures gradually fall back to around 10–15 °C (50–59 °F) before the onset of winter again lowers the surface to freezing levels.
Swimming in Lake Rosseau is very popular during the warmest months, from late June through early September, when surface temperatures reach comfortable levels. The lake’s exceptional water clarity and scenic surroundings make it ideal for swimming, boating, and other water sports. Public beaches and private cottages provide convenient access, with calm bays offering safe areas for recreational swimming. Outside the summer season, the cold water makes swimming unsafe and uncomfortable, though Lake Rosseau remains a year-round attraction for nature lovers and photographers.