Saint Lawrence River — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in the Saint Lawrence River, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in the Saint Lawrence River today is 22.7°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 |
|---|---|---|---|
| JUL 1 | 17.8°C | 20.0°C | |
| JUL 2 | 17.9°C | 20.0°C | |
| JUL 3 | 18.1°C | 20.0°C | |
| JUL 4 | 18.7°C | 20.0°C | |
| JUL 5 | 23.3°C | 20.0°C | |
| JUL 6 | 23.3°C | 20.0°C | |
| JUL 7 | 23.3°C | 20.0°C | |
| JUL 8 | 23.1°C | 20.0°C | |
| JUL 9 | 20.0°C | 22.6°C | |
| JUL 10 | 20.0°C | 22.4°C | |
| JUL 11 | 20.0°C | 22.3°C | |
| JUL 12 | 20.0°C | 22.2°C | |
| JUL 13 | 20.0°C | 22.0°C | |
| JUL 14 | 20.0°C | 21.9°C | |
| JUL 15 | 20.0°C | 21.8°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 | 2°C | 6°C | 9°C |
| February | 2°C | 6°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 | 10°C | 17°C | 22°C |
| July | 17°C | 20°C | 24°C |
| August | 17°C | 21°C | 24°C |
| September | 11°C | 16°C | 20°C |
| October | 8°C | 13°C | 16°C |
| November | 3°C | 8°C | 16°C |
| December | 3°C | 5°C | 8°C |
Saint Lawrence River: Water Temperature by Location
Saint Lawrence River: Weather Forecast
July 9
July 10
July 11
July 12
July 13
July 14
Location & Local Information
Source Lake Ontario
• location Kingston, Ontario / Cape Vincent, New York
Mouth Gulf of St. Lawrence / Atlantic Ocean
• location Quebec, Canada
Length 500 km (310 mi)
The Saint Lawrence River, stretching between the United States and Canada, is known for its clear, cold waters that vary greatly in temperature depending on the season. In the summer months, water temperatures typically range from 60°F to 70°F (15°C to 21°C), which can be inviting for swimmers in areas where conditions are safe. However, even during the warmest months, the water remains on the cooler side compared to other rivers, offering a refreshing experience for those seeking relief from the summer heat.
Swimming in the Saint Lawrence River is most popular in designated areas, such as near parks, beaches, and calmer stretches of the river. The Thousand Islands region, in particular, is a favored spot for water activities, offering stunning scenery and generally manageable conditions. However, swimmers should be aware of the river’s strong currents in certain areas, as well as colder temperatures in deeper sections or near the river’s flow into the Atlantic Ocean. Overall, the Saint Lawrence River provides a unique and scenic environment for swimming, best enjoyed in the summer and with proper attention to safety.