San Sebastián — Water Temperature, Sea Conditions & Trends
This page provides clear and up-to-date information about water temperature for San Sebastián (Basque Country, Spain). 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 San Sebastián help you plan your visit and choose the best time for swimming.
Current Water Temperature
Water temperature in San Sebastián in the Bay of Biscay today is 19°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
Water temperature in San Sebastián rose over the last 30 days but fell over the last week. Currently, the sea water temperature at this location matches the average for this day in previous years.
According to our forecast, Water temperature in San Sebastián will be 19.3°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 | 20.0°C | 18.3°C | |
| JUN 3 | 19.5°C | 18.8°C | |
| JUN 4 | 19.9°C | 18.3°C | |
| JUN 5 | 19.7°C | 18.3°C | |
| JUN 6 | 19.6°C | 18.0°C | |
| JUN 7 | 19.2°C | 18.8°C | |
| JUN 8 | 19.2°C | 18.0°C | |
| JUN 9 | 19.1°C | 18.3°C | |
| JUN 10 | 19.2°C | 18.3°C | 19.2°C |
| JUN 11 | 18.3°C | 19.2°C | |
| JUN 12 | 18.5°C | 19.2°C | |
| JUN 13 | 18.8°C | 19.2°C | |
| JUN 14 | 18.5°C | 19.2°C | |
| JUN 15 | 18.8°C | 19.3°C | |
| JUN 16 | 19.3°C | 19.3°C | |
| JUN 17 | 18.8°C | 19.3°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.
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
San Sebastián, known locally as Donostia, sits on the sheltered Bay of Biscay in Spain’s Basque Country and is famed for its urban beaches and scenic harbor. The sea here follows a temperate Atlantic pattern: winter water temperatures typically range from 12–14 °C, spring brings a gradual rise to about 13–16 °C, summer is the warmest period with typical values between 18–21 °C, and autumn cools back to roughly 15–17 °C. Local conditions can cause short-term variations — wind, tides and occasional upwelling influence surface temperatures — but these seasonal bands give a reliable expectation for visitors planning time in the water.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 11°C | 13°C | 15°C |
| February | 10°C | 12°C | 14°C |
| March | 11°C | 13°C | 15°C |
| April | 11°C | 14°C | 16°C |
| May | 13°C | 16°C | 20°C |
| June | 16°C | 19°C | 23°C |
| July | 19°C | 22°C | 24°C |
| August | 20°C | 23°C | 25°C |
| September | 19°C | 21°C | 24°C |
| October | 14°C | 19°C | 22°C |
| November | 13°C | 17°C | 19°C |
| December | 12°C | 15°C | 16°C |
* Click on a month to view detailed water temperature data.
San Sebastián: Weather Forecast
June 11
June 12
Location, Beaches & Local Information
Nearby Beaches & Facilities
Atardecer En Zurriola
Beach Of La Concha / Kontxa Hondartza
Beach Of La Concha
Playa De La Concha
Zurriola Beach / Zurriolaka Hondartza
Ondaretta Beach
Isla Santa Clara
Playa De La Ondarreta
Playa De Kalaburtza
Swimming Conditions
Swimming and beach holidays in San Sebastián suit a mix of tastes, from family-friendly bathing to active surf sessions. La Concha’s curved bay is relatively sheltered and often offers calmer waters ideal for casual swimming and paddling, while Ondarreta provides a more open beach experience and Zurriola is popular with surfers and bodyboarders when Atlantic swells are present. Lifeguard coverage and beach facilities are concentrated in the main summer months, and waters at 18–21 °C are generally comfortable for most swimmers; outside summer many local swimmers and surfers use wetsuits for longer sessions when temperatures are in the mid-teens. Open-water events, swimming lessons and marked bathing zones are common in season, but visitors should always heed local safety advice about currents and weather, and make practical arrangements for changing and gear if planning extended sea activity.