The best time to visit San Sebastián and Bilbao is from late May to June or in September, when days are warm, the sea is swimmable, and the August crowds have either not arrived or gone home. The Basque coast is green because it rains a lot, in every month, so pack a light waterproof whatever the season. Summers are mild rather than hot, and winters are cool but rarely freezing by the sea.
The climate in numbers
The figures below are 1981–2010 averages from AEMET, the Spanish weather agency, for Bilbao airport, and for the Igeldo station on the hill above San Sebastián (which runs a little cooler than the beach front).
- Bilbao: average highs of about 13°C (55°F) in January and 26°C (79°F) in August; around 1,130 mm of rain a year, on about 124 days.
- San Sebastián (Igeldo): average highs of about 11°C (52°F) in January and 22–23°C (72–73°F) in August; around 1,500 mm of rain a year, on about 141 days.
- Wettest months: October to January, with November the wettest of all.
- Driest months: June and July.
Rain here often means a grey morning of fine drizzle (locals call it txirimiri) that clears later, rather than a whole washed-out day. Now and then a warm, dry south wind blows down from the mountains and can push the temperature above 30°C for a day or two, sometimes even in spring or autumn.
Month by month
- January and February. Cool, wet and quiet, with short days and the lowest hotel prices. San Sebastián's Tamborrada drum parade on 20 January and the opening of the cider-house season in mid-January are good reasons to come.
- March and April. Changeable, with sunny spells between showers. Easter week brings many Spanish visitors, so book ahead if your trip falls then.
- May and June. One of the best times: long days, green hills, and average highs of about 18–20°C in San Sebastián and 21–23°C in Bilbao. The sea is still fresh for swimming in May but warms through June.
- July. Usually the driest month and properly summery. Bilbao BBK Live (a big music festival) and San Sebastián's Jazzaldia jazz festival are usually held in July (check each year's dates), and beaches start filling up.
- August. Peak season. The warmest weather, the busiest beaches and the highest prices, especially during the Semana Grande fiestas (San Sebastián, the week of 15 August) and Aste Nagusia (Bilbao, nine days from the Saturday after 15 August).
- September. Often the best month overall: the sea is at its warmest, the weather is still summery for much of the month and crowds thin after the first week. San Sebastián hosts the Bandera de La Concha rowing regatta on the first two Sundays of the month and its international film festival in late September (San Sebastián Festival), when hotels fill fast.
- October. Mild at first, then the autumn rains arrive. Good for food, city sightseeing and the wine harvest inland in Rioja Alavesa.
- November and December. Wet and grey, but quiet, and the pintxo bars and museums are at their most local. On 21 December both cities hold the Santo Tomás fair, with farmers' stalls and talo (corn flatbread) with chorizo.
Festival dates change slightly each year, so check the official event calendar at Turismo Euskadi before you book. For background on the fiestas and traditions, see our guide to Basque language and culture.
Crowds and prices
Hotels in San Sebastián are among the most expensive in Spain in July and August and during the film festival, and the best-located ones sell out months ahead. Bilbao is generally easier and cheaper, except during Aste Nagusia, big concerts and major football matches. Spanish public holidays and long weekends, such as Easter, 12 October, 1 November and the long weekend around 6 and 8 December, also bring a rush of domestic visitors. If you can travel in May, June or September, you get most of the summer weather for a lot less.
Beach or city trip?
If swimming and sunbathing matter, aim for July to mid-September and accept that you will share La Concha with many others. If the trip is mostly about food, the Guggenheim and walking the old towns, any month works: in winter you simply plan museum and pintxo time around the showers. Inland, Vitoria-Gasteiz and Rioja Alavesa are drier but colder in winter and hotter in summer than the coast.
For planning the rest of the trip, see our San Sebastián travel guide and Bilbao travel guide, and where to base yourself in San Sebastián or Bilbao.
Staying connected
On the Basque coast the weather changes fast, so being able to check the hourly forecast, the rain radar and the surf before you head to the beach or a coastal walk really helps. A data eSIM for Spain gives you local mobile data from the moment you land without removing your own SIM. Not sure how much to buy? See how much data you need.