Iskar Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Iskar Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Iskar Reservoir today is 19.3°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming. 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 3 | 17.8°C | 18.0°C | |
| JUN 4 | 17.8°C | 18.0°C | |
| JUN 5 | 17.7°C | 18.0°C | |
| JUN 6 | 18.2°C | 18.0°C | |
| JUN 7 | 18.2°C | 18.0°C | |
| JUN 8 | 18.2°C | 18.0°C | |
| JUN 10 | 19.3°C | 18.0°C | |
| JUN 11 | 18.0°C | 19.2°C | |
| JUN 12 | 18.0°C | 19.2°C | |
| JUN 13 | 18.0°C | 19.1°C | |
| JUN 14 | 18.0°C | 19.0°C | |
| JUN 15 | 18.0°C | 19.0°C | |
| JUN 16 | 18.0°C | 18.9°C | |
| JUN 17 | 18.0°C | 18.8°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 | 2°C | 6°C | 10°C |
| February | 2°C | 6°C | 10°C |
| March | 3°C | 8°C | 12°C |
| April | 6°C | 10°C | 14°C |
| May | 8°C | 14°C | 20°C |
| June | 12°C | 18°C | 23°C |
| July | 16°C | 21°C | 26°C |
| August | 16°C | 21°C | 26°C |
| September | 12°C | 18°C | 23°C |
| October | 10°C | 14°C | 18°C |
| November | 6°C | 10°C | 13°C |
| December | 2°C | 6°C | 10°C |
Iskar Reservoir: Water Temperature by Location
Iskar Reservoir: Weather Forecast
June 9
June 10
June 11
June 12
June 13
Location & Local Information
The Iskar Reservoir (Язовир Искър) near Sofia is a large man-made lake whose surface temperatures vary considerably through the year. In winter the water commonly sits close to freezing, around 0–6 °C (32–43 °F), while spring sees a gradual rise to roughly 6–15 °C (43–59 °F). In summer surface temperatures can reach approximately 18–26 °C (64–79 °F) on warm spells, though deeper water remains noticeably cooler. In autumn the temperature typically drops back through a range of about 10–18 °C (50–64 °F) as air temperatures fall and thermal stratification changes.
Swimming at Iskar Reservoir is not uniformly regulated in a single way: some shorelines and bays are used recreationally and people do swim there, but other areas are restricted or strongly discouraged. Because the reservoir is an important source for water supply and hydroelectric infrastructure, there are zones with intake works, steep banks, sudden depth changes, submerged objects and boat traffic that pose real hazards. Water quality can also vary by location and season. For those considering swimming it is advisable to check local rules and signage, choose supervised or commonly used spots, and be aware that many sections have no lifeguards or formal beach facilities.