Istanbul — Water Temperature, Sea Conditions & Trends
This page provides clear and up-to-date information about water temperature for Istanbul (Istanbul Province, Turkey). It includes the current water temperature, daily data for the last month presented in a simple chart, and a 7-day forecast. The page also compares today’s value with typical averages for this period, shows usual monthly ranges during the year, and lists nearby beaches with short descriptions. Local weather for the next few days and general details about Istanbul help you plan your visit and choose the best time for swimming.
Current Water Temperature
Water temperature in Istanbul in the Sea of Marmara today is 21°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 68°F (20°C) to 74°F (23°C). The water is warm and pleasant for swimming, and in this range, one can stay in the water for extended periods without the risk of hypothermia. This is the ideal temperature for relaxation, swimming, and water sports. Families with children, as well as outdoor enthusiasts, will enjoy swimming and time spent in the water. For most people, this is the optimal temperature for a comfortable beach experience.
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
Water temperature in Istanbul has risen over the last week and month. Currently, the sea water temperature at this location matches the average for this day in previous years.
According to our forecast, Water temperature in Istanbul will be 21.0°C in the next 7 days. See the table below for daily data for the upcoming week.
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| JUN 2 | 18.2°C | 18.3°C | |
| JUN 3 | 18.4°C | 18.8°C | |
| JUN 4 | 19.2°C | 19.0°C | |
| JUN 5 | 19.8°C | 19.5°C | |
| JUN 6 | 20.3°C | 19.8°C | |
| JUN 7 | 21.4°C | 19.5°C | |
| JUN 8 | 21.5°C | 19.5°C | |
| JUN 9 | 21.4°C | 20.3°C | |
| JUN 10 | 21.1°C | 20.3°C | 21.1°C |
| JUN 11 | 20.3°C | 21.1°C | |
| JUN 12 | 20.0°C | 21.1°C | |
| JUN 13 | 20.5°C | 21.0°C | |
| JUN 14 | 20.8°C | 21.0°C | |
| JUN 15 | 20.8°C | 21.0°C | |
| JUN 16 | 21.0°C | 21.0°C | |
| JUN 17 | 21.0°C | 21.0°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.
Water temperature data for this location is gathered from various sources, including buoys and satellite sea and ocean surface maps provided by the NOAA agency. We also incorporate data from local authorities in each specific location worldwide to ensure more accurate temperature readings.
Annual Water Temperature Overview by Month
Monthly Water Temp Ranges
Annual Water Temperature Trend
Istanbul sits where the Black Sea meets the Sea of Marmara, with the Bosphorus Strait running through the city, so water temperatures vary by coast and season. In winter (December–February) sea temperatures generally fall to around 6–12 °C, with the Black Sea side usually at the colder end and sheltered Marmara bays slightly warmer. During spring (March–May) waters warm progressively to roughly 10–18 °C. Summer (June–August) brings the warmest conditions, with the Sea of Marmara and southern bays commonly reaching about 22–26 °C while northern Black Sea shores tend to be cooler, about 20–23 °C. In autumn (September–November) temperatures typically decline to roughly 14–20 °C as the seas lose summer heat. Local factors such as shallow bays, river inflows and wind can produce short-term variations.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 7°C | 10°C | 13°C |
| February | 6°C | 9°C | 11°C |
| March | 7°C | 9°C | 11°C |
| April | 7°C | 11°C | 15°C |
| May | 12°C | 16°C | 20°C |
| June | 17°C | 21°C | 25°C |
| July | 21°C | 24°C | 29°C |
| August | 23°C | 25°C | 28°C |
| September | 20°C | 23°C | 26°C |
| October | 14°C | 20°C | 24°C |
| November | 10°C | 17°C | 20°C |
| December | 7°C | 13°C | 15°C |
* Click on a month to view detailed water temperature data.
Istanbul: Weather Forecast
June 11
June 12
June 13
Location, Beaches & Local Information
Nearby Beaches & Facilities
Kilyos Kumburgaz Beach
Caddebostan Plaji 1
Caddebostan Beach
Erenkoy Halk Plaji
Sheraton Istanbul Atakoy Hotel Sheraton
Atarli Beach
Swimming Conditions
Swimming and beach holiday options reflect that diversity: popular public beaches and private clubs on the Marmara and Black Sea coasts offer sand, facilities and lifeguards mainly in July and August, and the Princes’ Islands provide accessible swims and calmer waters in summer. The Black Sea resorts north of the city are scenic and good for beach days but often have cooler water. Open-water swimming in the Bosphorus occurs as organized events, but regular crossings are affected by strong currents and heavy maritime traffic and are not comparable to sheltered beach swimming. Visitors planning a beach holiday should choose sheltered Marmara bays for the warmest water, check seasonal services and local conditions, and expect cooler sea temperatures outside the peak summer months.