Bilbao is green because it rains. That is the honest starting point, and it shapes the answer more than anything else: this is the Atlantic coast, not the Mediterranean, and it gets more rainfall in a year than London does.
Which does not mean avoid it. It means picking your month deliberately, and knowing that the ferries themselves run on a season, which narrows the choice further than most guides mention.
The short answer
- Best overall: late May to early July, and September. Warm, drier, and either side of the August crush.
- Best for atmosphere: August, for Aste Nagusia, if you do not mind crowds.
- Best for value: October to April, when both fares and hotels drop sharply.
- Hardest for ferries: November to March, when sailings reduce. More on that below.
Bilbao month by month
| Month | Typical daytime high | Rain | Notes |
|---|---|---|---|
| January | Around 13°C | Wettest months | Mild for a British winter, quiet, cheap |
| February | Around 14°C | Wet | Carnival, and still very quiet |
| March | Around 16°C | Wet | Plymouth route restarts late in the month |
| April | Around 17°C | Showery | Parks in bloom, good value |
| May | Around 20°C | Improving | One of the best months |
| June | Around 23°C | Drier | Long days, not yet crowded |
| July | Around 25°C | Driest | BBK Live, busy |
| August | Around 26°C | Dry but humid | Aste Nagusia, peak crowds and fares |
| September | Around 24°C | Rain returning | Still summery, far calmer |
| October | Around 21°C | Wet | Last of the Plymouth sailings |
| November | Around 16°C | Wettest months | Ferries drop to winter frequency |
| December | Around 14°C | Wet | Christmas lights and markets |
Note what the table does not say: it never gets properly cold. Winter daytime highs sit around 13 to 14°C, which is milder than most of Britain. The trade is rain, not frost.
The bit most guides miss: the ferries have a season too
If you are sailing rather than flying, this constrains your trip more than the weather does.
- Portsmouth to Bilbao: two return sailings a week April to November, dropping to one a week from November to March.
- Rosslare to Bilbao: same pattern, two a week in season and one a week over winter.
- Plymouth to Santander: stops entirely from early November to late March.
- Portsmouth to Santander: the only crossing that runs all year.
So a February trip to Bilbao by sea means one sailing a week in each direction, and your dates are set by the ship rather than by you. Check the full 2026 timetable before fixing anything else.
Conversely, off-season is when fares are lowest, and a winter city break in Bilbao is a genuinely good idea if you can make the sailings work. Our guide to the cheapest crossing to Spain explains what actually moves the price.
Festivals worth planning around
Aste Nagusia, Bilbao’s Semana Grande
Nine days of fireworks competitions, street performance, Basque rural sports and open-air concerts, beginning on the Saturday after 15 August each year. It is the biggest week in the city’s calendar, and the streets around the Casco Viejo and the Arenal do not really stop.
Two things follow from that. Accommodation and ferry fares are at their highest, and both go early. And if you want a quiet Bilbao, this is the one week to avoid.
- Dates and programme: Bilbao Turismo
Bilbao BBK Live
A large open-air music festival held over a weekend in early July on Kobetamendi, the hillside above the city. International headliners, and a site with a view back down over Bilbao.
Dates move year to year, so check the official site rather than trusting a guide. If you are going, book the crossing at the same time as the tickets: Portsmouth to Bilbao runs twice a week at that point in the season, so there is not much flexibility.
- Official website: bilbaobbklive.com
Christmas and New Year
December brings lights along the Gran Vía, a market on the Arenal and the Olentzero, the Basque coal-merchant figure who brings presents instead of Father Christmas. Quiet, atmospheric, and built around long lunches rather than sightseeing.
Bear in mind the winter ferry frequency above if you are planning this one by sea.
What to do when it rains, because it will
Bilbao is unusually well set up for wet weather, which is presumably no accident.
- The Guggenheim and the Museo de Bellas Artes, the latter free on Wednesdays
- The covered Mercado de la Ribera, one of the largest food markets in Europe
- Pintxo bars in the arcaded Plaza Nueva, which is sheltered by design
- The metro, which is an architectural attraction in its own right
Full detail, including which museums are free on which days, is in our guide to things to do in Bilbao. Save the Artxanda funicular for a clear day, since in drizzle you pay for a view of cloud.
Arriving by ferry
Two direct sailings reach Bilbao, from Portsmouth on the Galicia and from Rosslare on the Santoña. Both are two-night crossings over the Bay of Biscay.
Worth knowing in winter: Biscay is rough between November and March, and while a ship this size rarely cancels, you will feel it. A cabin with a window helps, and taking something for seasickness before you feel unwell works better than after.
Whenever you sail, remember the terminal is at Zierbena, 13 miles outside the city. Plan the transfer before you arrive, particularly on a wet February morning. See port to city centre for the options, and getting around Bilbao without a car once you are there.
If the weather looks marginal, our sister site FerryWeather forecasts wind and sea state for the Bay of Biscay crossing itself.
