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 12.3°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 54°F (12°C) to 60°F (15°C). The water is significantly warmer, and swimming becomes possible for most people. However, caution may still be required for prolonged stays in the water, as extended exposure can cause discomfort. This is a suitable temperature range for short swims and for those accustomed to cooler water. For more comfortable swimming, it is recommended to use proper gear. 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 |
|---|---|---|---|
| OCT 26 | 15.9°C | 18.0°C | |
| OCT 27 | 15.5°C | 18.0°C | |
| OCT 28 | 15.2°C | 18.0°C | |
| OCT 29 | 14.0°C | 18.0°C | |
| OCT 30 | 15.7°C | 18.0°C | |
| OCT 31 | 15.0°C | 18.0°C | |
| NOV 1 | 14.6°C | 12.4°C | |
| NOV 2 | 12.3°C | 12.4°C | |
| NOV 3 | 12.4°C | 12.3°C | |
| NOV 4 | 12.4°C | 12.3°C | |
| NOV 5 | 12.4°C | 12.3°C | |
| NOV 6 | 12.4°C | 12.3°C | |
| NOV 7 | 12.4°C | 12.3°C | |
| NOV 8 | 12.4°C | 12.3°C | |
| NOV 9 | 12.4°C | 12.3°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 | 27°C | 31°C |
| August | 23°C | 27°C | 31°C |
| September | 21°C | 25°C | 29°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
November 3
November 4
November 5
November 6
November 7
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.