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 27.4°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 79°F (26°C) to 82°F (28°C). This is very warm water, allowing for extended stays without any discomfort. Swimming in these conditions will be particularly enjoyable, making it the ideal temperature range for those who want to relax in the sea. Additionally, water in this temperature range is suitable for children and elderly people, as it is comfortable for prolonged stays. 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 |
|---|---|---|---|
| AUG 13 | 29.6°C | 27.0°C | |
| AUG 14 | 29.6°C | 27.0°C | |
| AUG 15 | 29.6°C | 27.0°C | |
| AUG 16 | 27.8°C | 27.0°C | |
| AUG 17 | 27.8°C | 27.0°C | |
| AUG 18 | 27.8°C | 27.0°C | |
| AUG 19 | 27.8°C | 27.0°C | |
| AUG 20 | 27.4°C | 27.0°C | |
| AUG 21 | 27.0°C | 27.4°C | |
| AUG 22 | 27.0°C | 27.4°C | |
| AUG 23 | 27.0°C | 27.3°C | |
| AUG 24 | 27.0°C | 27.3°C | |
| AUG 25 | 27.0°C | 27.3°C | |
| AUG 26 | 27.0°C | 27.3°C | |
| AUG 27 | 27.0°C | 27.3°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 | 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
August 21
August 22
August 23
August 24
August 25
August 26
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.