Lake Saint John — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Saint John, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Saint John today is 25.5°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 |
|---|---|---|---|
| JUN 6 | 26.4°C | 26.5°C | |
| JUN 7 | 27.2°C | 26.5°C | |
| JUN 8 | 27.2°C | 26.5°C | |
| JUN 10 | 27.8°C | 26.5°C | |
| JUN 11 | 25.2°C | 26.5°C | |
| JUN 12 | 25.4°C | 26.5°C | |
| JUN 13 | 25.5°C | 26.5°C | |
| JUN 14 | 26.5°C | 25.6°C | |
| JUN 15 | 26.5°C | 25.6°C | |
| JUN 16 | 26.5°C | 25.7°C | |
| JUN 17 | 26.5°C | 25.7°C | |
| JUN 18 | 26.5°C | 25.8°C | |
| JUN 19 | 26.5°C | 25.8°C | |
| JUN 20 | 26.5°C | 25.9°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 | 8°C | 13°C | 19°C |
| February | 5°C | 11°C | 17°C |
| March | 8°C | 14°C | 20°C |
| April | 15°C | 19°C | 24°C |
| May | 20°C | 25°C | 29°C |
| June | 23°C | 27°C | 30°C |
| July | 24°C | 27°C | 30°C |
| August | 20°C | 23°C | 26°C |
| September | 24°C | 27°C | 29°C |
| October | 19°C | 23°C | 27°C |
| November | 13°C | 17°C | 21°C |
| December | 10°C | 13°C | 17°C |
Lake Saint John: Water Temperature by Location
Lake Saint John: Weather Forecast
June 13
June 14
June 15
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June 17
June 18
Location & Local Information
Lake Saint John, like many shallow inland lakes in Louisiana, experiences wide seasonal swings in water temperature. In winter months the surface water typically cools to roughly 45–60°F (7–16°C), with the coldest readings after extended cold spells. Spring brings steady warming, often rising into the 60–75°F (16–24°C) range as air temperatures moderate. Summer is when the lake is warmest; surface temperatures commonly reach 75–90°F (24–32°C) on hot days and can be even warmer in very shallow, sheltered bays. During autumn the water gradually cools again, with temperatures commonly falling into the 65–80°F (18–27°C) band. Actual temperatures vary by depth, shading, inflow, and recent weather, and can change rapidly after storms or prolonged heat.
Swimming at Lake Saint John is generally allowed in areas where public access and recreation are intended, but it’s conditioned by local regulations and water-quality conditions. Designated swim spots or public beaches are preferred because they are monitored and maintained; in other spots, aquatic vegetation, submerged hazards, bacteria, harmful algal blooms, and wildlife such as alligators can make swimming unsafe. Before entering the water, check for posted advisories or closures, avoid swimming after heavy rains when runoff can raise bacterial levels, and follow any guidance from local authorities to ensure a safe experience.