Climate averages 1991–2020
Donostia / San Sebastián weather
in September.
A mild, wet month: the 3rd warmest and the 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Donostia / San Sebastián: daytime highs average 21.4°C and nights cool to about 15.6°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 96 mm of rain on roughly 13 days, which makes September a wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 33 min on an average September day.
The nearest other city in this atlas is Pamplona (61 km away). In September its highs average 22.2°C, 0.8°C warmer than Donostia / San Sebastián, with 50 mm of rain.
Among the 93 cities listed in Spain, Donostia / San Sebastián ranks 89th of 93 for the warmest September highs and 92nd of 93 for the driest September (rainfall, lowest first). The mean September high of those 93 cities is 25.5°C; Donostia / San Sebastián is 4.1°C cooler than that mean.
From September to October, average highs fall by 2.7°C to 18.8°C, and monthly rainfall rises from 96 mm to 128 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Donostia / San Sebastián climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 11.2°C6.5°C | 6.5°C | 135 | 15.4 | 9.49 h |
| February | 11.6°C6.3°C | 6.3°C | 123 | 14.1 | 10.510 h |
| March | 13.7°C7.8°C | 7.8°C | 114 | 13.9 | 11.912 h |
| April | 15.1°C9.2°C | 9.2°C | 127 | 16.1 | 13.413 h |
| May | 18.0°C12.0°C | 12.0°C | 117 | 15.4 | 14.715 h |
| June | 20.6°C14.7°C | 14.7°C | 93 | 12.7 | 15.315 h |
| July | 22.4°C16.7°C | 16.7°C | 82 | 12.6 | 15.115 h |
| August | 23.3°C17.4°C | 17.4°C | 89 | 12.9 | 14.014 h |
| September, selected | 21.4°C15.6°C | 15.6°C | 96 | 12.9 | 12.513 h |
| October | 18.8°C13.3°C | 13.3°C | 128 | 14.3 | 11.111 h |
| November | 14.2°C9.6°C | 9.6°C | 170 | 15.7 | 9.810 h |
| December | 11.9°C7.5°C | 7.5°C | 138 | 15.1 | 9.09 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Pamplona in SeptemberSpain · 61 kmHigh 22.2°C · Low 12.7°C · 50 mm rain
- Gasteiz / Vitoria in SeptemberSpain · 77 kmHigh 21.9°C · Low 12.2°C · 43 mm rain
- Bilbao in SeptemberSpain · 77 kmHigh 21.5°C · Low 15.9°C · 65 mm rain
- Barakaldo in SeptemberSpain · 82 kmHigh 21.7°C · Low 15.7°C · 65 mm rain
- Logroño in SeptemberSpain · 102 kmHigh 23.3°C · Low 12.9°C · 32 mm rain
- Pau in SeptemberFrance · 131 kmHigh 21.5°C · Low 12.6°C · 98 mm rain
- Santander in SeptemberSpain · 149 kmHigh 22.6°C · Low 15.3°C · 78 mm rain
- Burgos in SeptemberSpain · 177 kmHigh 22.0°C · Low 11.0°C · 39 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Donostia / San Sebastián) is explained once on the Donostia / San Sebastián year overview and on the Sources, method and limits page.