Marion Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Marion Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Marion Reservoir today is 28.8°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature is above 82°F (28°C). This is very warm water, which may feel almost hot to most people. Swimming in such conditions is perfect for those seeking relaxation and comfort in the water. These waters are often preferred for relaxation in hot weather, as the water temperature does not cool the body significantly. However, it is important to remember that in such warm waters, caution is necessary, as prolonged exposure without rest can lead to overheating. 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 14 | 25.7°C | 26.1°C | |
| JUL 15 | 28.1°C | 26.1°C | |
| JUL 16 | 28.1°C | 26.1°C | |
| JUL 17 | 28.1°C | 26.1°C | |
| JUL 18 | 28.8°C | 26.1°C | |
| JUL 19 | 28.9°C | 26.1°C | |
| JUL 20 | 29.1°C | 26.1°C | |
| JUL 21 | 29.1°C | 26.1°C | |
| JUL 22 | 26.1°C | 28.7°C | |
| JUL 23 | 26.1°C | 28.5°C | |
| JUL 24 | 26.1°C | 28.4°C | |
| JUL 25 | 26.1°C | 28.3°C | |
| JUL 26 | 26.1°C | 28.1°C | |
| JUL 27 | 26.1°C | 28.0°C | |
| JUL 28 | 26.1°C | 27.9°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 | 1°C | 3°C | 6°C |
| February | 1°C | 4°C | 7°C |
| March | 1°C | 8°C | 15°C |
| April | 9°C | 14°C | 19°C |
| May | 13°C | 18°C | 23°C |
| June | 19°C | 23°C | 26°C |
| July | 23°C | 26°C | 30°C |
| August | 23°C | 26°C | 28°C |
| September | 21°C | 24°C | 27°C |
| October | 15°C | 18°C | 21°C |
| November | 7°C | 12°C | 17°C |
| December | 1°C | 4°C | 8°C |
Marion Reservoir: Water Temperature by Location
Marion Reservoir: Weather Forecast
July 22
July 23
July 24
July 25
July 26
Location & Local Information
Marion Reservoir’s water temperature follows typical mid-continental seasonal patterns. In winter the surface often approaches near-freezing conditions, roughly 32–40°F (0–4°C). As air temperatures warm in spring, surface readings commonly rise into the 50–70°F range (10–21°C), with considerable variability depending on recent weather. During summer the shallow bays and surface waters can reach the mid-70s to mid-80s °F, about 24–29°C, while deeper or wind-exposed areas remain cooler. In autumn surface temperatures generally fall back into the 50s–70s °F (13–21°C) as cooling resumes. Thermal stratification can produce much cooler water below the surface even in warm months, and levels and temperatures will vary with inflows, wind, and reservoir operations.
Swimming is allowed at Marion Reservoir in many of the recreation areas, but it is subject to posted rules and seasonal restrictions set by the managing agency. There are often no lifeguards on duty, and swimmers should be cautious of boat traffic, sudden drop-offs, submerged timber, and occasional algae or water-quality advisories that can limit safe swimming. Because the reservoir is managed for flood control, power generation and water supply as well as recreation, water levels and conditions change; checking local signage and advisories before entering the water is recommended.