Lake Marathon — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Marathon, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Marathon 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 |
|---|---|---|---|
| SEP 10 | 25.3°C | 25.0°C | |
| SEP 12 | 24.8°C | 25.0°C | |
| SEP 13 | 24.6°C | 25.0°C | |
| SEP 14 | 24.5°C | 25.0°C | |
| SEP 15 | 24.7°C | 25.0°C | |
| SEP 16 | 24.9°C | 25.0°C | |
| SEP 17 | 24.7°C | 25.0°C | |
| SEP 18 | 25.0°C | 24.2°C | |
| SEP 19 | 25.0°C | 24.3°C | |
| SEP 20 | 25.0°C | 24.3°C | |
| SEP 21 | 25.0°C | 24.4°C | |
| SEP 22 | 25.0°C | 24.4°C | |
| SEP 23 | 25.0°C | 24.4°C | |
| SEP 24 | 25.0°C | 24.5°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 | 6°C | 10°C | 14°C |
| February | 6°C | 10°C | 13°C |
| March | 6°C | 10°C | 13°C |
| April | 10°C | 14°C | 19°C |
| May | 14°C | 20°C | 25°C |
| June | 19°C | 24°C | 29°C |
| July | 21°C | 26°C | 32°C |
| August | 22°C | 27°C | 33°C |
| September | 20°C | 25°C | 30°C |
| October | 13°C | 18°C | 21°C |
| November | 10°C | 15°C | 20°C |
| December | 8°C | 12°C | 15°C |
Lake Marathon: Water Temperature by Location
Lake Marathon: Weather Forecast
September 18
September 19
September 20
September 21
September 22
Location & Local Information
Lake Marathon (Λίμνη Μαραθώνα) is a man-made reservoir in Attica that serves primarily as a water supply for Athens, so its physical and thermal characteristics reflect both seasonal weather and management of water levels. Surface temperatures typically rise from around 8–12 °C (46–54 °F) in winter to about 12–18 °C (54–64 °F) in spring. In summer the surface often warms to roughly 22–28 °C (72–82 °F), especially in calm, sunny periods, while autumn sees a cooling trend to roughly 14–20 °C (57–68 °F). Actual temperatures vary with depth, wind, inflow, and recent rainfall, so surface readings can be several degrees warmer than deeper water even in summer.
Because Marathon is a drinking-water reservoir, swimming and most forms of recreational water contact are officially prohibited to protect water quality and public health; management rules and signage typically forbid bathing, and enforcement can include fines. Safety concerns—such as sudden depth changes, cold deeper water, and limited rescue access—also underpin the restrictions. While some people may visit the surrounding parkland for walking and sightseeing, entering the water is not permitted and is not recommended for either legal or safety reasons.