Sarnia — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Sarnia, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Sarnia today is 20.9°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 |
|---|---|---|---|
| JUN 3 | 17.4°C | 17.5°C | |
| JUN 4 | 17.5°C | 17.5°C | |
| JUN 5 | 19.0°C | 17.5°C | |
| JUN 6 | 19.2°C | 17.5°C | |
| JUN 7 | 20.0°C | 17.5°C | |
| JUN 8 | 20.4°C | 17.5°C | |
| JUN 10 | 20.8°C | 17.5°C | |
| JUN 11 | 17.5°C | 20.7°C | |
| JUN 12 | 17.5°C | 20.6°C | |
| JUN 13 | 17.5°C | 20.4°C | |
| JUN 14 | 17.5°C | 20.2°C | |
| JUN 15 | 17.5°C | 20.1°C | |
| JUN 16 | 17.5°C | 19.9°C | |
| JUN 17 | 17.5°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 | 1°C | 5°C | 9°C |
| February | 1°C | 5°C | 9°C |
| March | 1°C | 6°C | 11°C |
| April | 1°C | 9°C | 16°C |
| May | 6°C | 14°C | 21°C |
| June | 13°C | 18°C | 22°C |
| July | 17°C | 20°C | 24°C |
| August | 17°C | 21°C | 23°C |
| September | 11°C | 16°C | 20°C |
| October | 8°C | 13°C | 17°C |
| November | 3°C | 8°C | 16°C |
| December | 3°C | 5°C | 8°C |
Sarnia: Weather Forecast
June 9
June 10
June 11
June 12
June 13
June 14
Location & Local Information
Sarnia sits on the southeastern shore of Lake Huron, one of the Great Lakes known for its vast size and cold, clean water. The water temperature here changes significantly throughout the year due to the lake’s depth and exposure to strong currents. In winter, the surface water temperature drops close to freezing, averaging 0–2 °C (32–36 °F), and ice may form along the shoreline. During spring, the water slowly begins to warm but remains cold at around 5–10 °C (41–50 °F). By mid to late summer, nearshore areas around Sarnia reach more comfortable temperatures of 18–22 °C (64–72 °F), while offshore waters stay several degrees cooler. In autumn, the water gradually cools again to around 10–15 °C (50–59 °F) as the air temperature drops.
Swimming in Sarnia is popular during the warmer months, especially at Canatara Park Beach, which is well-known for its clear water and sandy shore. The official swimming season typically runs from late June to early September, when the water is warm enough for comfortable bathing and lifeguards are on duty. Outside these months, the lake remains too cold for safe or enjoyable swimming. Despite the short season, Lake Huron’s clean waters and scenic beaches make Sarnia a favorite spot for summer swimming, kayaking, and waterfront relaxation.