Climate - San Sebastian (Basque Country)

The climate of San Sebastián is temperate oceanic, with mild, rainy winters and quite cool summers. We are in the north of Spain, where the climate is much cooler and more humid than in the rest of the country.
The city (called Donostia in Basque) is located in the north-east of the Basque Country, at the mouth of the Urumea River, and about 15 kilometers (9 miles) from the border with France. There are three beaches: Ondarreta, La Concha and la Zurriola.
The wind blows frequently from the ocean, and can be strong, especially in the cold half of the year. On the other hand, the warm and dry southerly wind, which descends from the Cantabrian Mountains, can cause sudden increases in temperature due to the foehn effect.
Although the climate is mild, cold waves in winter are more intense than in the rest of the northern Spanish coast, due to its proximity to France. In addition, the rains are particularly abundant.
The average temperature of the coldest month (January) is of 8.5 °C (47 °F), that of the warmest month (August) is of 20 °C (68 °F). Here are the average temperatures (the weather station is located on mount Igueldo, a hill of 260 meters or 850 feet).

Precipitation amounts to 1,510 millimeters (59.4 inches) per year: it is therefore abundant. It ranges from 85 mm (3.3 in) in the driest month (July) to 170 mm (6.7 in) in the wettest (November). Here is the average precipitation.

Winter, from December to February, is mild and rainy. Atlantic disturbances regularly pass over northern Spain, bringing rain and cloudy skies.
With the wind from the south, the temperature can exceed 20 °C (68 °F) even in the middle of winter.
There may also be cold spells, although they are quite rare. Generally, on the coldest nights of the year, there are only slight frosts, but sometimes it can get very cold. In February 1956, the temperature dropped to -12 °C (10.5 °F), while in January 1985, it dropped to -10 °C (14 °F). From 2000 to 2020, it dropped to -5.5 °C (22 °F) in December 2001 and in February 2012.
Snow in San Sebastián is rare, however, from time to time, the city can be covered with snow. In February 1996, even 30 cm (12 in) of snow fell. More recently, snow thickness reached 5 cm (2 in) in January 2010 and February 2018.

The summer, from June to August or mid-September, is quite cool. The rains are quite frequent even in this season, and the sun doesn't shine very often. Fog can form at night and early in the morning.
Occasionally, the southerly wind can bring intense heat, usually only for a day or two. On the hottest days of the year, the temperature typically reaches 35 °C (95 °F), but can sometimes reach higher values. In July 2019 and 2020, it reached 39 °C (102 °F). In 2003, it had reached 38 °C (100.5 °F) in June and 38.5 °C (101 °F) in August.



On average, there are around 1,775 sunshine hours per year. Here are the average sunshine hours per day.

The sea temperature ranges between 12 °C (54 °F) and 22 °C (72 °F). The sea is cool even in summer, although it is a little less cool than in Galicia and Asturias. Here are the average sea temperatures.

Best Time

The best time to visit San Sebastián is from June to mid-September, since it is the mildest and least rainy of the year.
To go to the beach, the preferable months are July and August (and the beginning of September if the weather is good).

Back to the Basque Country.

San Sebastian - Weather by month

Based on the period 1991-2020

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In January, the coldest month of the year, the weather in San Sebastian is usually mild. The average temperature is of 8.6 °C (48 °F), with a minimum of 6.2 °C (43.2 °F) and a maximum of 11.1 °C (52 °F).
On the coldest nights of the month, the temperature usually drops to around 0 °C (32 °F). However, it dropped to -3.2 °C (26.2 °F) in January 2007.
On the warmest days of the month, the temperature usually reaches around 18 °C (64 °F). However, it reached 21 °C (69.8 °F) in January 1999.
Precipitation amounts to 140 mm (5.5 in), distributed over 13 days.
The day lasts on average 9 hours and 25 minutes.
There are on average 3 hours of sunshine per day. So, the sun shines 34% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).
The average sea temperature is of 13 °C (55 °F). Therefore, the sea is very cold for swimming.

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In February, the weather in San Sebastian is usually mild. The average temperature is of 8.8 °C (48 °F), with a minimum of 6 °C (42.8 °F) and a maximum of 11.6 °C (52.9 °F).
On the coldest nights of the month, the temperature usually drops to around 0.5 °C (32.5 °F). However, it dropped to -5.3 °C (22.5 °F) in February 2012.
On the warmest days of the month, the temperature usually reaches around 19 °C (66.5 °F). However, it reached 25.6 °C (78.1 °F) in February 2019.
Precipitation amounts to 110 mm (4.3 in), distributed over 12 days.
The day lasts on average 10 hours and 35 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 36% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).
The average sea temperature is of 12.5 °C (54.5 °F). Therefore, the sea is very cold for swimming.

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In March, the weather in San Sebastian is usually mild. The average temperature is of 10.6 °C (51 °F), with a minimum of 7.7 °C (45.9 °F) and a maximum of 13.6 °C (56.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 2 °C (36 °F). However, it dropped to -4.7 °C (23.5 °F) in March 2005.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 22.5 °C (72 °F). However, it reached 25.6 °C (78.1 °F) in March 2007.
Precipitation amounts to 115 mm (4.5 in), distributed over 12 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 39% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).
The average sea temperature is of 12.5 °C (54.5 °F). Therefore, the sea is very cold for swimming.

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In April, the weather in San Sebastian is usually mild. The average temperature is of 12.0 °C (54 °F), with a minimum of 8.8 °C (47.8 °F) and a maximum of 15.1 °C (59.2 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 4 °C (39.5 °F). However, it dropped to 1.6 °C (34.9 °F) in April 1996.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 25 °C (77 °F). However, it reached 30.1 °C (86.2 °F) in April 2010.
Precipitation amounts to 140 mm (5.5 in), distributed over 14 days.
The day lasts on average 13 hours and 30 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 39% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).
The average sea temperature is of 13 °C (56 °F). Therefore, the sea is very cold for swimming.

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In May, the weather in San Sebastian is usually very mild. The average temperature is of 14.7 °C (58 °F), with a minimum of 11.4 °C (52.5 °F) and a maximum of 18 °C (64.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 7 °C (44.5 °F). However, it dropped to 3.6 °C (38.5 °F) in May 2019.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 28.5 °C (83.5 °F). However, it reached 33.2 °C (91.8 °F) in May 1996.
Precipitation amounts to 120 mm (4.7 in), distributed over 12 days.
The day lasts on average 14 hours and 40 minutes. So the days are long.
There are on average 6 hours of sunshine per day. So, the sun shines 40% of the time.
The average humidity is 76%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 15.5 °C (59.5 °F). Therefore, the sea is cold for swimming.

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In June, the weather in San Sebastian is usually very mild. The average temperature is of 17.2 °C (63 °F), with a minimum of 14.2 °C (57.6 °F) and a maximum of 20.3 °C (68.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 10.5 °C (51 °F). However, it dropped to 8.8 °C (47.8 °F) in June 1992.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 31.5 °C (88.5 °F). However, it reached 38 °C (100.4 °F) in June 2003.
Precipitation amounts to 90 mm (3.5 in), distributed over 11 days.
The day lasts on average 15 hours and 20 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 6.5 hours of sunshine per day. So, the sun shines 41% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 18.5 °C (65.5 °F). Therefore, the sea is very cool for swimming.

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In July, the weather in San Sebastian is usually warm. The average temperature is of 19.2 °C (66 °F), with a minimum of 16.3 °C (61.3 °F) and a maximum of 22 °C (71.6 °F).
On the coldest nights of the month, the temperature usually drops to around 13 °C (55 °F). However, it dropped to 10 °C (50 °F) in July 1993.
On the warmest days of the month, the temperature usually reaches around 32.5 °C (91 °F). However, it reached 39 °C (102.2 °F) in July 2019.
Precipitation amounts to 85 mm (3.3 in), distributed over 10 days.
The day lasts on average 15 hours and 0 minutes. So the days are long.
There are on average 6.5 hours of sunshine per day. So, the sun shines 42% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 21 °C (69.5 °F). Therefore, the sea is cool for swimming.

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In August, the warmest month of the year, the weather in San Sebastian is usually warm. The average temperature is of 19.8 °C (68 °F), with a minimum of 16.8 °C (62.2 °F) and a maximum of 22.9 °C (73.2 °F).
On the coldest nights of the month, the temperature usually drops to around 13 °C (56 °F). However, it dropped to 11.6 °C (52.9 °F) in August 1998.
On the warmest days of the month, the temperature usually reaches around 32.5 °C (90.5 °F). However, it reached 38.6 °C (101.5 °F) in August 2003.
Precipitation amounts to 115 mm (4.5 in), distributed over 11 days.
The day lasts on average 13 hours and 55 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 44% of the time.
The average humidity is 78%. Hence, the air is normally humid.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 22 °C (71 °F). Therefore, the sea is cool for swimming.

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In September, the weather in San Sebastian is usually very mild. The average temperature is of 18.0 °C (64 °F), with a minimum of 14.9 °C (58.8 °F) and a maximum of 21.2 °C (70.2 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 10.5 °C (50.5 °F). However, it dropped to 8 °C (46.4 °F) in September 2002.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 30 °C (86 °F). However, it reached 35.6 °C (96.1 °F) in September 2016.
Precipitation amounts to 110 mm (4.3 in), distributed over 10 days.
The day lasts on average 12 hours and 25 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 48% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 20.5 °C (69 °F). Therefore, the sea is cool for swimming.

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In October, the weather in San Sebastian is usually very mild. The average temperature is of 15.6 °C (60 °F), with a minimum of 12.6 °C (54.7 °F) and a maximum of 18.6 °C (65.5 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 6.5 °C (43.5 °F). However, it dropped to 0 °C (32 °F) in October 2018.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 26 °C (78.5 °F). However, it reached 29.8 °C (85.6 °F) in October 2001.
Precipitation amounts to 160 mm (6.3 in), distributed over 12 days.
The day lasts on average 11 hours and 0 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 41% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is 12 kph (7 mph).
The average sea temperature is of 18 °C (64 °F). Therefore, the sea is cold for swimming.

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In November, the weather in San Sebastian is usually mild. The average temperature is of 11.6 °C (53 °F), with a minimum of 9 °C (48.2 °F) and a maximum of 14.1 °C (57.4 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 3.5 °C (38 °F). However, it dropped to -1.4 °C (29.5 °F) in November 2007.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 21.5 °C (70.5 °F). However, it reached 25.6 °C (78.1 °F) in November 2015.
Precipitation amounts to 170 mm (6.7 in), distributed over 13 days.
The day lasts on average 9 hours and 40 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 35% of the time.
The average humidity is 76%. Hence, the air is normally humid.
The average wind speed is 13 kph (8 mph).
The average sea temperature is of 15.5 °C (59.5 °F). Therefore, the sea is cold for swimming.

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In December, the weather in San Sebastian is usually mild. The average temperature is of 9.4 °C (49 °F), with a minimum of 7 °C (44.6 °F) and a maximum of 11.9 °C (53.4 °F).
On the coldest nights of the month, the temperature usually drops to around 1 °C (33.5 °F). However, it dropped to -5.6 °C (21.9 °F) in December 2001.
On the warmest days of the month, the temperature usually reaches around 18 °C (64.5 °F). However, it reached 22.2 °C (72 °F) in December 2015.
Precipitation amounts to 150 mm (5.9 in), distributed over 13 days.
The day lasts on average 9 hours and 0 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 3 hours of sunshine per day. So, the sun shines 33% of the time.
The average humidity is 77%. Hence, the air is normally humid.
The average wind speed is 14 kph (9 mph).
The average sea temperature is of 13.5 °C (56.5 °F). Therefore, the sea is very cold for swimming.