Monthly climate guide
San Sebastián weather in September
September in San Sebastián is typically warm, with average daytime highs around 22°C (72°F) and night-time lows near 17°C (63°F). The month usually brings about 62 mm of rain (some rain) and is often cloudy. Daytime highs are 2°C cooler than August and 3°C warmer than October.
What stands out in September
- Skies are at their clearest this time of year.
- Only 2 months are warmer in San Sebastián than September.
- September brings early autumn to San Sebastián.
- There's little difference between day and night (around 5°C).
Avg high
22°C
72°F
Avg low
17°C
63°F
Rainfall
62 mm
some rain
Humidity
76%
relative
Sky
63%
cloud · often cloudy
San Sebastián weather by month
Show the monthly averages as a table
| Month | Avg high | Avg low | Rain | Humidity | Cloud cover |
|---|---|---|---|---|---|
| January | 11°C / 52°F | 8°C / 46°F | 151 mm | 83% | 78% |
| February | 11°C / 52°F | 7°C / 45°F | 121 mm | 81% | 71% |
| March | 13°C / 56°F | 9°C / 47°F | 101 mm | 81% | 70% |
| April | 15°C / 59°F | 11°C / 51°F | 97 mm | 80% | 71% |
| May | 18°C / 64°F | 13°C / 55°F | 91 mm | 81% | 72% |
| June | 21°C / 69°F | 16°C / 60°F | 85 mm | 81% | 69% |
| July | 23°C / 73°F | 18°C / 65°F | 61 mm | 80% | 65% |
| August | 24°C / 75°F | 19°C / 65°F | 47 mm | 77% | 65% |
| September | 22°C / 72°F | 17°C / 63°F | 62 mm | 76% | 63% |
| October | 19°C / 67°F | 15°C / 58°F | 89 mm | 77% | 68% |
| November | 15°C / 59°F | 11°C / 52°F | 160 mm | 81% | 76% |
| December | 13°C / 55°F | 9°C / 48°F | 129 mm | 82% | 75% |
What to pack for September
- T-shirts plus a light layer for the evening
- Comfortable trainers or sandals for long walks
- A small travel umbrella, just in case
Is September a good time to visit San Sebastián?
Compare the months in the chart above to find your ideal window.
Best time to visit San Sebastián →Other Spain cities in September
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San Sebastián weather in September. WeatherCompare, 2026 (NASA POWER / ERA5, 2011–2020 monthly averages). https://weathercompare.eu/weather/spain/san-sebastian/september
<a href="https://weathercompare.eu/weather/spain/san-sebastian/september">San Sebastián weather in September</a> (WeatherCompare)
<iframe src="https://weathercompare.eu/embed/spain/san-sebastian" width="300" height="160" style="border:0;border-radius:12px" loading="lazy" title="San Sebastián weather in September"></iframe> <p style="font-size:12px"><a href="https://weathercompare.eu/weather/spain/san-sebastian/september">San Sebastián weather in September</a> – WeatherCompare</p>
San Sebastián in September: quick answers
Is September a good time to visit San Sebastián?
Yes. September is one of the best months for San Sebastián, with highs around 22°C and about 62 mm of rain.
How warm is San Sebastián in September?
Average highs are about 22°C (72°F) and average lows about 17°C (63°F), based on 10 years of daily data.
Does it rain a lot in San Sebastián in September?
San Sebastián typically gets around 62 mm of rain in September — some rain.
Figures are long-term averages for the area around San Sebastián (NASA POWER / ERA5, 2011–2020), not a forecast for a specific year. For upcoming days, see the live multi-source forecast.