Playa de Ondarreta — Sea temperature now
Spanish beach near San Sebastián.
Warm water with a light chop and a light breeze — great swimming conditions.
Location
Playa de Ondarreta on the map, with nearby beaches and live sea temperatures.
7-day forecast
Water, air, waves, wind and UV outlook for the week ahead.
Monthly sea temperature averages
Typical year-round water temperature, based on regional climatology.
Best time to swim in Playa de Ondarreta
The sea in Playa de Ondarreta peaks in August, when the water averages around 26°C.
The main swimming season runs from June – October, when surface temperatures stay comfortable for extended sessions.
On average, 5 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
Shoulder months like May and November are noticeably cooler but often quieter, with fewer crowds and steadier weather.
Outside peak season the water drops toward 16°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable.
The coldest month is typically February at around 14°C, when cold-water swimmers dominate the coast.
Playa de Ondarreta sea temperature history
Long-term climatology for Playa de Ondarreta shows an annual mean sea temperature of 19°C, ranging from 14°C in winter to 26°C at the summer peak.
The seasonal swing is roughly 12°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.
Recent decades have trended slightly warmer at Playa de Ondarreta, in line with regional sea-surface temperature records for the wider basin.
Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.
Playa de Ondarreta sea temperature: frequently asked questions
What is the warmest month to swim in Playa de Ondarreta?
August is the warmest month in Playa de Ondarreta, when the sea averages about 26°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Playa de Ondarreta?
The coldest month in Playa de Ondarreta is typically February, when the water averages around 14°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Playa de Ondarreta without a wetsuit?
The main swimming season in Playa de Ondarreta runs from June – October — about 5 months a year when the sea sits above 20°C, the level most swimmers describe as pleasant without a wetsuit.
Do I need a wetsuit in Playa de Ondarreta?
Outside peak summer the water in Playa de Ondarreta drops toward 16°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable. In peak months most swimmers go without.
What is the average sea temperature in Playa de Ondarreta?
The long-term annual mean sea temperature in Playa de Ondarreta is about 19°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Playa de Ondarreta?
The live reading at the top of this page shows the current sea temperature in Playa de Ondarreta, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
Year-round sea temperature
Best swim months: Jun – Jul – Aug – Sep – Oct
| Month | Sea | Comfort |
|---|---|---|
| Jan | 15°C | Bracing |
| Feb | 14°C | Bracing |
| Mar | 15°C | Bracing |
| Apr | 16°C | Bracing |
| May | 18°C | Pleasant |
| Jun | 22°C | Warm |
| Jul | 25°C | Warm |
| Aug ⭐ | 26°C | Hot |
| Sep | 24°C | Warm |
| Oct | 21°C | Pleasant |
| Nov | 18°C | Pleasant |
| Dec | 16°C | Bracing |