Lake Simcoe — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Simcoe, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Simcoe today is 18.5°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 15 | 19.8°C | 21.0°C | |
| SEP 16 | 19.5°C | 21.0°C | |
| SEP 17 | 19.3°C | 21.0°C | |
| SEP 18 | 19.2°C | 21.0°C | |
| SEP 19 | 19.2°C | 21.0°C | |
| SEP 20 | 19.1°C | 21.0°C | |
| SEP 21 | 19.1°C | 21.0°C | |
| SEP 22 | 18.9°C | 21.0°C | |
| SEP 23 | 21.0°C | 18.6°C | |
| SEP 24 | 21.0°C | 18.8°C | |
| SEP 25 | 21.0°C | 18.9°C | |
| SEP 26 | 21.0°C | 19.0°C | |
| SEP 27 | 21.0°C | 19.1°C | |
| SEP 28 | 21.0°C | 19.3°C | |
| SEP 29 | 21.0°C | 19.4°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 | 3°C | 6°C |
| February | 0°C | 4°C | 7°C |
| March | 0°C | 3°C | 6°C |
| April | 2°C | 8°C | 14°C |
| May | 6°C | 14°C | 22°C |
| June | 12°C | 18°C | 24°C |
| July | 18°C | 23°C | 27°C |
| August | 19°C | 24°C | 29°C |
| September | 17°C | 21°C | 25°C |
| October | 13°C | 16°C | 19°C |
| November | 3°C | 9°C | 15°C |
| December | 1°C | 5°C | 8°C |
Lake Simcoe: Water Temperature by Location
Lake Simcoe: Weather Forecast
September 23
September 24
September 25
September 26
September 27
September 28
Location & Local Information
Lake Simcoe is a large, relatively shallow inland lake in Central Ontario that serves as a major recreational hub, leading to significant seasonal water temperature variations. In the deep winter months, the entire lake typically develops a thick ice cover, with water temperatures near freezing, generally ranging from 0∘C to 5∘C (32∘F to 41∘F), making it popular for ice fishing. In the peak summer season (July and August), the shallower nature of the lake allows the surface water to warm significantly, typically reaching a comfortable range of 20∘C to 24∘C (68∘F to 75∘F), making it highly suitable for swimming.
Swimming is widely permitted and highly encouraged throughout Lake Simcoe, with numerous public beaches along its shoreline in municipalities like Barrie, Georgina, and Innisfil. Many of these beaches, such as Centennial Beach in Barrie, are supervised by lifeguards during the peak summer season, confirming their status as safe, designated swimming areas. However, the various regional health units routinely monitor the water for E. coli bacteria. Swimmers must always check for and adhere to swimming advisories, which are frequently posted when bacterial counts, often linked to runoff after heavy rain, temporarily exceed safe limits for water contact.