Donostia / San Sebastián weather in December
In December, Donostia / San Sebastián has daytime highs averaging 12 °C, nights around 7.3 °C, with 15 wet days, and a sea temperature of 14 °C. Figures are 1991–2020 climate normals.
- 11.9°C Average high
- 7.3°C Average low
- 15days Wet days
- 142mm Rainfall
- 13.8°C Sea temperature
- 9.0h Daylight
Daily temperatures through December
How December develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 December | 12.3 °C | 7.9 °C | 53 % |
| 11–20 December | 11.8 °C | 7.3 °C | 44 % |
| 21–31 December | 11.7 °C | 6.8 °C | 44 % |
- Rain is most likely over days 1–10 of December (53 % of days) and least likely over days 21–31 (44 %).
What to expect
| Measure | Typical December | Share of the month |
|---|---|---|
| Days above 25 °C | 0 of 31 | 0 % |
| Days above 30 °C | 0 of 31 | 0 % |
| Days below 0 °C | 0.5 of 31 | 2 % |
| Days with more than 1 mm rain | 15 of 31 | 47 % |
Conditions in December
| Measure | Average |
|---|---|
| Mean temperature | 9.5 °C |
| Record high (1991–2020) | 20 °C |
| Record low (1991–2020) | -2.9 °C |
| Relative humidity | 79 % |
| Wind speed | 20 km/h |
| Cloud cover | 70 % |
Where Donostia / San Sebastián ranks in December
| Ranking | Position | Value |
|---|---|---|
| Warmest sea temperatures in Europe in December | 46thof 50 | 14 °C |
| The warmest places in Europe in December | 47thof 50 | 12 °C |
December compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| January | 11.2 °C | 144 mm | 70 % |
| February | 11.6 °C | 130 mm | 66 % |
| October | 18.8 °C | 134 mm | 63 % |
| November | 14.2 °C | 178 mm | 68 % |
| December | 11.9 °C | 142 mm | 70 % |
See all twelve months for Donostia / San Sebastián
- December is the 10th warmest month here.
- It is the 10th driest month of the year.
- It ranks 12th for least cloud cover.
- Days last about 9.0 hours from sunrise to sunset.
- It rains on 15 of 31 days — 47 % of the month.
- Nights are about 4.6 °C cooler than the middle of the day.
- The hottest December day on record since 1991 reached 20 °C, 8.3 °C above the usual daytime high.
- Beach score: 1 / 100 — see how this is calculated.
Nearby destinations in December
| Destination | Avg high | Wet days | Sea |
|---|---|---|---|
| Donostia / San Sebastián | 12 °C | 15 | 14 |
| Pamplona | 8.9 °C | 10 | – |
| Gasteiz / Vitoria | 9.0 °C | 11 | – |
| Bilbao | 13 °C | 14 | 14 |
| Logroño | 9.8 °C | 10 | – |
| Santander | 13 °C | 14 | 14 |
| Burgos | 7.5 °C | 9 | – |
| Bordeaux | 11 °C | 11 | – |
| Zaragoza | 12 °C | 6 | – |
QuestionsDecember in Donostia / San Sebastián, answered
How warm is Donostia / San Sebastián in December?
Daily highs average 12 °C and nights fall to about 7.3 °C, a spread of 4.6 °C between afternoon and dawn. That makes December the 10th warmest month of the year here.
Does it rain much in Donostia / San Sebastián in December?
December averages 142 mm of rain, spread over about 15 of the 31 days — 47 % of the month. Cloud cover averages 70 % of the sky.
Is the sea warm enough to swim in December?
The sea averages 14 °C off Donostia / San Sebastián in December. Most people find water below 20 °C bracing and above 25 °C comfortable for a long swim; this figure is a monthly surface average, so a sheltered bay on a still afternoon can be warmer.
How long are the days in December?
Donostia / San Sebastián averages 9.0 hours between sunrise and sunset in December. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.