Spain
San Sebastian in September: weather, sea & travel advice
This month's data profile
Rain shapes the decision
San Sebastian in September is climatically well suited to city breaks, active holidays and hiking and family holidays. The average daily high is around 22 °C, and the sea is about 21 °C. With about 12 rainy days it is wet.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
72/100 · #3
Warmth
#3
Dryness
#4
Sun
#6
Sea warmth
#3
Published best categories: Overall, Beach, City break, Active, Family
San Sebastian · SeptemberPhoto: Ander.gd · CC BY-SA 4.0Climate facts
- Average high
- 22 °C
- Average low
- 17 °C
- Sea
- 21 °C
- Rainy days (est.)
- 12 rainy days (est.)
- Sun (est.)
- 5 h/day
- Humidity
- 76 %
Climate evidence with direct month comparison
The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.
| Month | Avg high °C | Avg low °C | Rainy days (est.) | Precipitation mm | Sun h/day (est.) | Humidity % | Wind m/s | Sea °C | Score |
|---|---|---|---|---|---|---|---|---|---|
| August | 24 | 19 | 10 | 55 | 6.6 | 77 | 2.5 | 22 | 83 |
| September (selected) | 22 | 17 | 12 | 84 | 5.3 | 76 | 2.7 | 21 | 72 |
| October | 19 | 14 | 13 | 102 | 3.4 | 78 | 3.0 | 18 | 56 |
How do the previous and next months compare?
Baseline: September (72/100)
Positive and negative values show the change from the selected month.
| Score Δ | Average high Δ | Average low Δ | Rainy days Δ | Rain Δ | Sun Δ | Humidity Δ | Wind Δ | Sea Δ | |
|---|---|---|---|---|---|---|---|---|---|
| August | +11 | +2 °C | +1.7 °C | -2.3 | -28.8 mm | +1.3 h | +0.8 % | -0.2 m/s | +1.4 °C |
| October | -16 | -2.9 °C | -2.6 °C | +0.9 | +17.8 mm | -1.9 h | +1.6 % | +0.3 m/s | -2.5 °C |
All twelve months in context
Find a place to stay
Where to stay in San Sebastian
Compare available stays, prices and cancellation terms for San Sebastian on Booking.com.
Booking.comFind places to stayAffiliate link: there is no extra cost to you.
Useful next decisions
Frequently asked questions
How warm is San Sebastian in September?
The average daily high is around 22 °C, with an average daily low of about 17 °C.
Can you swim in San Sebastian in September?
The sea is about 21 °C (refreshing).
Does it rain a lot in San Sebastian in September?
The curated estimate is about 12 rainy days per month, not a directly measured long-term average. Total precipitation averages around 84 mm for the month. A rainy day does not mean all-day rain.
When is the best time to visit San Sebastian?
By the climate score, June, July, August and September are the strongest months for San Sebastian. For a beach trip: June, July, August and September. September is one of them.