Verdict: Good month
San Sebastián Weather in September
September hits the sweet spot in San Sebastián — highs around 23°C (73°F), ideal for a full day on foot. Expect showers on roughly 14 days of the month — rarely trip-ruining, worth planning around. Overall, September is a solid month to visit San Sebastián.
Average high
23°C / 73°F
Average low
16°C / 61°F
Rain days
~14
Precipitation
149 mm
What to pack for San Sebastián in September
- Summer clothes, plus one light layer for air-con and evenings
- Rain gear is non-negotiable — expect rain on roughly 14 days
- Comfortable walking shoes — every guide on this site assumes you'll use them
September against the rest of the year
Warmest in San Sebastián: Aug (25°C / 77°F) · Coolest: Jan (12°C / 54°F) · Wettest: Dec (~17 rain days)
12°
6°
Jan
15°
8°
Feb
16°
8°
Mar
17°
10°
Apr
20°
12°
May
22°
15°
Jun
24°
17°
Jul
25°
18°
Aug
23°
16°
Sep
21°
14°
Oct
16°
10°
Nov
14°
8°
Dec
Daily highs / lows in °C · bars show rain days per month · ERA5 climate normals (2020–2024)