San Sebastian weather by month

When to go to San Sebastian

For beach weather, look at months where the daytime average clears 25°C and rainy days stay low: none reach a 25°C average here, so San Sebastian suits city breaks and walking more than beach holidays; the warmest is August. November is the wettest month (178 mm, about 16 rainy days) and July the driest (82 mm). The sea is warmest in August at 22.3°C and coolest in February at 12.1°C.

Getting there

A direct flight from London Gatwick to San Sebastián Airport (EAS, 16 km from Donostia / San Sebastián) takes roughly 1 h 54 min - short-haul (up to 4.5 h) by UK standards. Time-zone: Europe/Madrid.

Records and extremes, 1991-2020

The hottest day recorded in San Sebastian between 1991 and 2020 reached 39.7°C on 30 July 2020; the coldest fell to -3.8°C on 27 February 2018. In August one day in ten tops 28.1°C and about 5% of days pass 30°C; in January one night in ten drops to 2.0°C or below. The wettest single month of the period was November 2019 with 456 mm, against a November average of 178 mm.

Winter and spring: bring layers and keep plans flexible

Winter suits travellers who prefer cool days to warmth and do not need swimming weather. December averages 12°C by day, January slips to 11°C, and February returns to 12°C, so a warm layer and waterproof jacket are more useful than beachwear. January and February nights average 6°C, making evenings noticeably colder. Spring improves gradually rather than bringing an abrupt change: March remains cool, April reaches 15°C, and May feels milder at 18°C. Rain is still a regular consideration, with April averaging 16 rainy days. May is the better spring choice for spending longer outdoors, but its 16°C sea remains chilly for casual swimming. Keep outdoor plans movable rather than relying on uninterrupted sunshine.

Summer: the best balance of warmth and swimming weather

Summer offers San Sebastian's strongest weather for a holiday centred on being outdoors, without average daytime temperatures reaching 25°C. June is the cooler option, with days around 21°C and a 19°C sea that may still feel brisk. July brings slightly warmer days and the fewest rainy days, making it the better choice if avoiding rain matters most. August has the warmest air and sea, with the water averaging 22°C, so it suits travellers who prioritise swimming. Both months have nights around 17°C; a light layer is sensible for evenings. Expect changeable spells rather than guaranteed clear skies, even with an average of 6 hours of sunshine daily.

Autumn: September holds its warmth, then conditions turn cooler

September is the strongest autumn choice, retaining a summer-like balance of 22°C days and a 21°C sea. It suits travellers who want to swim without choosing the hottest month, although rain remains part of the picture. October is a clearer step towards cooler weather: daytime averages fall to 19°C, evenings need another layer, and the sea drops to 18°C. It is better suited to walking than a holiday built around long swims. November brings a sharper change, with days around 14°C and 16 rainy days. As the wettest month, it calls for waterproof clothing and flexible plans, particularly if most of your holiday would otherwise be spent outdoors.