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 24.2°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 75°F (23°C) to 79°F (26°C). This is a very comfortable temperature for swimming, and many people can enjoy prolonged stays in the water without feeling cold. The water is pleasantly warm, making it ideal for relaxation and water sports. This temperature range is particularly popular among tourists, as it combines comfort and safety for health. 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 22 | 22.9°C | 20.9°C | |
| JUL 23 | 23.1°C | 20.9°C | |
| JUL 24 | 23.1°C | 20.9°C | |
| JUL 25 | 23.1°C | 20.9°C | |
| JUL 26 | 23.6°C | 20.9°C | |
| JUL 27 | 23.9°C | 20.9°C | |
| JUL 28 | 24.0°C | 20.9°C | |
| JUL 29 | 24.2°C | 20.9°C | |
| JUL 30 | 20.9°C | 24.0°C | |
| JUL 31 | 20.9°C | 23.8°C | |
| AUG 1 | 20.5°C | 23.6°C | |
| AUG 2 | 20.5°C | 23.5°C | |
| AUG 3 | 20.5°C | 23.3°C | |
| AUG 4 | 20.5°C | 23.1°C | |
| AUG 5 | 20.5°C | 22.9°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 | 21°C | 25°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 29
July 30
July 31
August 1
August 2
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.