| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 11.3° | 6.1° | 162.1mm | 16 | 42 |
| February | 11.9° | 6.1° | 127.9mm | 13.9 | 46 |
| March | 13.9° | 7.6° | 119.9mm | 13.6 | 53 |
| April | 15.4° | 8.9° | 113.7mm | 15.3 | 55 |
| May | 18.1° | 11.4° | 121.6mm | 15 | 64 |
| June | 20.6° | 14.4° | 103.6mm | 14 | 72 |
| July | 22° | 16.3° | 88.6mm | 13.2 | 74 |
| August | 22.9° | 16.8° | 108.3mm | 13.6 | 73 |
| September | 21.4° | 15° | 113.5mm | 12.4 | 75 |
| October | 19.3° | 13° | 147.1mm | 13.1 | 72 |
| November | 14.3° | 8.9° | 219.4mm | 16.1 | 52 |
| December | 12.2° | 7° | 155mm | 15.1 | 45 |
January in Donostia / San Sebastián averages a daily high of 11.3°C with nights around 6.1°C. Expect roughly 16 wet days totalling 162.1mm. Demanding conditions — pack for it and plan indoor options.
February in Donostia / San Sebastián averages a daily high of 11.9°C with nights around 6.1°C. Expect roughly 13.9 wet days totalling 127.9mm. Demanding conditions — pack for it and plan indoor options.
March in Donostia / San Sebastián averages a daily high of 13.9°C with nights around 7.6°C. Expect roughly 13.6 wet days totalling 119.9mm. Demanding conditions — pack for it and plan indoor options.
April in Donostia / San Sebastián averages a daily high of 15.4°C with nights around 8.9°C. Expect roughly 15.3 wet days totalling 113.7mm. Generally workable, with some weather to plan around.
May in Donostia / San Sebastián averages a daily high of 18.1°C with nights around 11.4°C. Expect roughly 15 wet days totalling 121.6mm. Generally workable, with some weather to plan around.
June in Donostia / San Sebastián averages a daily high of 20.6°C with nights around 14.4°C. Expect roughly 14 wet days totalling 103.6mm. Generally workable, with some weather to plan around.
July in Donostia / San Sebastián averages a daily high of 22°C with nights around 16.3°C. Expect roughly 13.2 wet days totalling 88.6mm. Generally workable, with some weather to plan around.
August in Donostia / San Sebastián averages a daily high of 22.9°C with nights around 16.8°C. Expect roughly 13.6 wet days totalling 108.3mm. Generally workable, with some weather to plan around.
September in Donostia / San Sebastián averages a daily high of 21.4°C with nights around 15°C. Expect roughly 12.4 wet days totalling 113.5mm. Comfortable conditions for being outdoors all day.
October in Donostia / San Sebastián averages a daily high of 19.3°C with nights around 13°C. Expect roughly 13.1 wet days totalling 147.1mm. Generally workable, with some weather to plan around.
November in Donostia / San Sebastián averages a daily high of 14.3°C with nights around 8.9°C. Expect roughly 16.1 wet days totalling 219.4mm. Demanding conditions — pack for it and plan indoor options.
December in Donostia / San Sebastián averages a daily high of 12.2°C with nights around 7°C. Expect roughly 15.1 wet days totalling 155mm. Demanding conditions — pack for it and plan indoor options.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Donostia / San Sebastián peaks at 75.
Based on 30 years of records, June–October scores highest for comfort in Donostia / San Sebastián, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 22.9°C.
November is the wettest, averaging 219.4mm of rain across roughly 16.1 wet days.
January is the coolest month, with average daily highs around 11.3°C.