San Sebastián in September
In September, San Sebastián averages 23°C (73°F) during the day and 16°C (60°F) at night, with around 12 days of rain (112 mm total).
High seasonConditions are comfortable for sightseeing without being sweltering. Plan for unsettled weather and bring rain gear.
September offers comfortable temperatures in San Sebastián, with some rain to plan around.
How September compares to the rest of the year in San Sebastián
September is one of the warmest months in San Sebastián (3rd of 12) and one of the driest months (12th of 12). Daytime temperature runs 5°C above the annual average (18°C). September runs 1°C cooler than August (24°C) and cools 3°C in October (20°C).
September sunrise & sunset in San Sebastián
Times shown for San Sebastián local time (Europe/Madrid), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in San Sebastián — September
Golden-hour and blue-hour windows for the 15th of September, in San Sebastián's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — San Sebastián in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (High season) and San Sebastián's popularity.
Crowds & pricing — September in San Sebastián
This is a busy month in San Sebastián — not the absolute peak, but tourist numbers are clearly elevated. You'll feel it at headline attractions on weekends and in the historic centre, though side streets and lesser-known sights stay manageable. Prices are above off-season but not at their summit. A good week for first-time visitors who want everything open without the worst of the crush.
Why this tier: excellent tourism weather
Sun & mosquito risk — September in San Sebastián
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
San Sebastián in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 12°C / 53°F | 6°C / 43°F | 220 mm | 17 | — |
| February | 13°C / 56°F | 7°C / 44°F | 166 mm | 15 | — |
| March | 15°C / 58°F | 8°C / 46°F | 155 mm | 17 | — |
| April | 17°C / 62°F | 10°C / 49°F | 118 mm | 14 | — |
| May | 19°C / 66°F | 12°C / 53°F | 122 mm | 16 | — |
| June | 22°C / 71°F | 15°C / 59°F | 106 mm | 14 | — |
| July | 23°C / 74°F | 17°C / 63°F | 76 mm | 13 | — |
| August | 24°C / 75°F | 17°C / 63°F | 102 mm | 12 | — |
| September | 23°C / 73°F | 16°C / 60°F | 112 mm | 12 | — |
| October | 20°C / 69°F | 14°C / 56°F | 121 mm | 13 | — |
| November | 15°C / 60°F | 10°C / 50°F | 229 mm | 18 | — |
| December | 14°C / 57°F | 8°C / 47°F | 177 mm | 15 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for San Sebastián in September →
Frequently asked questions
How hot is San Sebastián in September?
In September, San Sebastián averages a high of 23°C (73°F) and a low of 16°C (60°F) — generally mild and pleasant.
Does it rain a lot in San Sebastián in September?
September can be fairly wet in San Sebastián, with about 12 rainy days on average.
Is September a good time to visit San Sebastián?
September is mild and pleasant. It suits travelers who are comfortable with mild and pleasant weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for San Sebastián in September?
Pack light layers for warm days and cooler evenings, plus a compact umbrella or rain jacket. See the full September packing list for San Sebastián for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.