If you’re checking the San Sebastian weather forecast right now, you’re probably staring at a row of little gray cloud icons and wondering if you should just cancel your trip. Don’t. Seriously, don’t. San Sebastian—or Donostia, as the locals call it—doesn't do "normal" weather. It has a personality. A moody, Atlantic, slightly stubborn personality that makes it one of the most beautiful places in Spain precisely because it refuses to be a sun-scorched desert.
I’ve spent enough time in the Basque Country to know that the forecast is basically a suggestion. You can wake up to a "100% chance of rain" on your phone, look out the window at La Concha Bay, and see nothing but blue sky and surfers. Ten minutes later? You’re sprinting for cover under a stone archway in the Parte Vieja because the sky just opened up. Then, like magic, the sun is back and the cobblestones are steaming.
The secret to enjoying this city isn't finding a week of perfect sun. It's understanding how the Bay of Biscay plays with the clouds.
Why the San Sebastian Weather Forecast Is Often a Liar
The main thing people get wrong is thinking that rain means the day is ruined. In San Sebastian, rain is often just a sirimiri. That’s the Basque word for a fine, misty drizzle. It’s light. It’s almost refreshing. Locals don’t even stop their outdoor coffee for it.
Because the city is tucked between the sea and the mountains, weather gets trapped. The Pyrenees act like a giant wall. This creates a microclimate where it might be pouring in the nearby hills of Irun but perfectly dry at the Peine del Viento sculpture.
Most weather apps use generic data models that don't account for these sudden shifts. If the forecast says it's going to rain all day, what it usually means is that it could rain at some point during those 24 hours. Honestly, a "partly cloudy" forecast is the sweet spot. It gives you that dramatic Basque light that makes the architecture pop and keeps the temperatures from getting too oppressive.
Understanding the Seasons in Donostia
You've got to pick your poison based on what you actually want to do. If you're here for the food, the weather barely matters. If you're here to tan, you need to be strategic.
- Winter (December - February): It's damp. It's chilly (usually 45°F to 55°F). But it's also incredibly cozy. This is when the city feels most authentic. There's something special about walking along the promenade in a thick coat with the waves crashing over the sea wall, then ducking into a bar for a glass of Rioja and a warm pintxo.
- Spring (March - May): Totally unpredictable. You'll see locals in shorts and tourists in parkas on the same street. This is the greenest time of year, but bring an umbrella. You'll definitely use it.
- Summer (June - August): This is the peak. But even in July, the San Sebastian weather forecast might only hit 75°F. It’s rarely "too hot," which is why half of Madrid flees to San Sebastian in August to escape the 100-degree heat of the south.
- Autumn (September - October): My personal favorite. The water is still warm from the summer sun, the crowds are gone, and the "La Gala" (the Film Festival) brings a buzz to the air. The light in October is golden and heavy.
What to Actually Pack (The Survival Kit)
Forget the "Spain = Sandals" rule. If you bring only flip-flops to San Sebastian in the spring or fall, you’re going to have a bad time.
You need layers. Start with a t-shirt, add a light sweater, and top it off with a high-quality, breathable raincoat. A "breathable" one is key because when it rains, the humidity spikes. If you wear a plastic poncho, you’ll just end up sweating on the inside while getting rained on on the outside. Not a great look.
Footwear is the second big hurdle. The Old Town has limestone floors that get incredibly slick when wet. I’ve seen more than one tourist do a cartoon-style slip-and-slide outside a cheesecake shop. Wear shoes with actual grip. Sneakers are fine; leather boots are better in winter.
And skip the cheap five-euro umbrellas you buy at the souvenir shops. The wind coming off the Atlantic will turn those inside out in three seconds flat. If you need an umbrella, get a sturdy one or just stick to a hooded jacket like the locals do.
Reading the Sky Like a Local
If you want to know what the weather is actually doing, look at Mount Igueldo. If the top of the mountain is "wearing a hat" (covered in low clouds), rain is almost certainly on the way. If the horizon over the water looks clear and sharp, you’ve probably got at least a few hours of good weather ahead.
Another pro tip: check the Spanish weather site AEMET. It’s the national meteorological agency. While Google Weather is okay for a general vibe, AEMET has localized sensors at the San Sebastian airport and in the city center that are much more dialed into the specific coastal patterns.
✨ Don't miss: Sloan Canyon National Conservation Area: Why You’re Likely Missing the Best Parts of Vegas
The Impact of the "Galerna"
Every now and then, San Sebastian gets hit by a Galerna. This is a sudden, violent coastal storm. One minute it’s a hot, still afternoon; the next, the wind shifts to the northwest, the temperature drops 10 degrees in minutes, and the sea goes wild. It’s spectacular to watch from a safe distance—like from behind the glass windows of a café—but you don't want to be out on a paddleboard when it hits.
Actionable Steps for Your Trip
Don't let a bad San Sebastian weather forecast ruin your mood. Instead, do this:
- Download the AEMET app: It's way more accurate for Northern Spain than the default weather app on your iPhone.
- Book a museum for the "red" days: If the forecast looks truly dismal, that’s your day for the San Telmo Museum or a long, multi-course lunch at a cider house in Astigarraga.
- Embrace the Sirimiri: Put your hood up and keep walking. The city is often at its most photogenic when the ground is wet and reflecting the streetlights.
- Check the Tides: In San Sebastian, the tide matters as much as the rain. At high tide, the beach at La Concha almost disappears. If you want a beach walk, check the tide charts along with the weather.
Basically, just be prepared to pivot. This city rewards people who are flexible. One minute you're eating gelato in the sun, and the next you're tucked into a corner bar eating txuleta. Both are perfect San Sebastian experiences.
Stop checking the 10-day forecast every hour. It’s going to change six times before you land anyway. Just pack your raincoat, bring your appetite, and get ready to enjoy one of the most atmospheric cities on the planet, rain or shine.