Climate - Guernsey (United Kingdom)

The climate of Guernsey is oceanic, cool and humid throughout the year.
The island is located in the English Channel, a short distance from the French coast of Lower Normandy, and belongs to Great Britain.
The average temperature ranges from 6.8 °C (44.2 °F) in February to 17 °C (62.5 °F) in August. Here are the average temperatures.

Precipitation amounts to 840 millimeters (33 inches) per year. The relatively wettest season is autumn, the least rainy is summer. Here is the average precipitation.

Winter, from December to February, is quite cold: temperatures are not so low, but wind and humidity can increase the sensation of cold. The sky is often cloudy, and rainfall is frequent. Sometimes, intense Atlantic depressions can cause wind storms.
Snowfalls are relatively rare and not abundant. Usually, cold spells are not intense and do not last long. The temperature rarely drops below -3 °C (26.5 °F), although the coldest record is -7.8 °C (18 °F), set in January 1963.

In spring, from March to May, the temperature slowly rises, and Atlantic fronts become a bit less frequent. In May, it is often still quite cold, especially in the first half of the month.

Summer, from June to August, is cool, with quite frequent rains, but also with a bit of good weather. Sometimes fog can form.
Hot days are rare: the temperature may not reach 25 °C (77 °F) for an entire month. However, it can sometimes exceed 30 °C (86 °F). The highest record is 32.5 °C (90.5 °F) and was set in August 1990 and in July 2016.

Autumn, from September to November, is gray, cloudy and rainy, and with each passing week, it gets progressively colder. In November, the wind is often moderate or strong.



The sun in Guernsey does not shine often from October to March (although it can come out between one disturbance and another), while from April to September, it shines for an acceptable number of hours. In one year, there are 1,865 hours of sunshine: we are at the levels of the English south coast, which is the highest in Great Britain. Here are the average sunshine hours per day.

The sea is cold all year round, however, from July to September the water temperature reaches 17/18 °C (62/64 °F). Here are the average sea temperatures.

Best Time

The best time to visit Guernsey runs from June to mid-September. July and August are the warmest months, or the least cool, however, it's better to bring a sweatshirt and a light jacket also in midsummer.

Guernsey - Weather by month

Based on the period 1991-2020

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In January, the weather in Guernsey is usually quite mild. The average temperature is of 7.2 °C (45 °F), with a minimum of 5.3 °C (41.6 °F) and a maximum of 9 °C (48.2 °F).
On the coldest nights of the month, the temperature usually drops to around 0.5 °C (32.5 °F). However, it dropped to -4.5 °C (23.9 °F) in January 1997.
On the warmest days of the month, the temperature usually reaches around 12 °C (54 °F). However, it reached 13.3 °C (55.9 °F) in January 2007.
Precipitation amounts to 95 mm (3.7 in), distributed over 15 days.
The day lasts on average 8 hours and 40 minutes.
There are on average 2 hours of sunshine per day. So, the sun shines 23% of the time.
The average humidity is 84%. Hence, the air is normally humid.
The average wind speed is 25 kph (15 mph).
The average sea temperature is of 10 °C (50 °F). Therefore, the sea is very cold for swimming.

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In February, the coldest month of the year, the weather in Guernsey is usually quite mild. The average temperature is of 6.8 °C (44 °F), with a minimum of 4.8 °C (40.7 °F) and a maximum of 8.8 °C (47.9 °F).
On the coldest nights of the month, the temperature usually drops to around 0 °C (32.5 °F). However, it dropped to -7.2 °C (19 °F) in February 1991.
On the warmest days of the month, the temperature usually reaches around 12 °C (53.5 °F). However, it reached 16.1 °C (61 °F) in February 2019.
Precipitation amounts to 70 mm (2.8 in), distributed over 11 days.
The day lasts on average 10 hours and 10 minutes.
There are on average 3 hours of sunshine per day. So, the sun shines 30% of the time.
The average humidity is 83%. Hence, the air is normally humid.
The average wind speed is 23 kph (14 mph).
The average sea temperature is of 9 °C (48 °F). Therefore, the sea is very cold for swimming.

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In March, the weather in Guernsey is usually quite mild. The average temperature is of 8.0 °C (46 °F), with a minimum of 5.7 °C (42.3 °F) and a maximum of 10.2 °C (50.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 2 °C (35.5 °F). However, it dropped to -3 °C (26.6 °F) in March 2018.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 15 °C (59 °F). However, it reached 18.6 °C (65.5 °F) in March 2012.
Precipitation amounts to 65 mm (2.6 in), distributed over 12 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 34% of the time.
The average humidity is 83%. Hence, the air is normally humid.
The average wind speed is 22 kph (13 mph).
The average sea temperature is of 9 °C (48 °F). Therefore, the sea is very cold for swimming.

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In April, the weather in Guernsey is usually mild. The average temperature is of 9.6 °C (49 °F), with a minimum of 6.9 °C (44.5 °F) and a maximum of 12.3 °C (54.2 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 3 °C (37.5 °F). However, it dropped to 0.1 °C (32.2 °F) in April 2013.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 18.5 °C (65 °F). However, it reached 24.5 °C (76.1 °F) in April 2020.
Precipitation amounts to 55 mm (2.2 in), distributed over 10 days.
The day lasts on average 13 hours and 50 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 47% of the time.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 10 °C (50 °F). Therefore, the sea is very cold for swimming.

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In May, the weather in Guernsey is usually mild. The average temperature is of 12.2 °C (54 °F), with a minimum of 9.3 °C (48.8 °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 6 °C (42.5 °F). However, it dropped to 1.9 °C (35.4 °F) in May 1997.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 22 °C (71.5 °F). However, it reached 25.9 °C (78.6 °F) in May 2003.
Precipitation amounts to 50 mm (2 in), distributed over 9 days.
The day lasts on average 15 hours and 25 minutes. So the days are long.
There are on average 7.5 hours of sunshine per day. So, the sun shines 49% of the time.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 12 °C (53.5 °F). Therefore, the sea is very cold for swimming.

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In June, the weather in Guernsey is usually very mild. The average temperature is of 14.7 °C (58 °F), with a minimum of 11.7 °C (53 °F) and a maximum of 17.7 °C (63.9 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 8.5 °C (47 °F). However, it dropped to 7 °C (44.6 °F) in June 1991.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 24.5 °C (76.5 °F). However, it reached 29.8 °C (85.6 °F) in June 1995.
Precipitation amounts to 45 mm (1.8 in), distributed over 7 days.
The day lasts on average 16 hours and 10 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 8 hours of sunshine per day. So, the sun shines 51% of the time.
The average humidity is 83%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 14 °C (57 °F). Therefore, the sea is very cold for swimming.

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In July, the weather in Guernsey is usually very mild. The average temperature is of 16.6 °C (62 °F), with a minimum of 13.7 °C (56.6 °F) and a maximum of 19.6 °C (67.3 °F).
On the coldest nights of the month, the temperature usually drops to around 11 °C (52 °F). However, it dropped to 8.7 °C (47.7 °F) in July 1996.
On the warmest days of the month, the temperature usually reaches around 26 °C (78.5 °F). However, it reached 32.6 °C (90.7 °F) in July 2016.
Precipitation amounts to 40 mm (1.6 in), distributed over 8 days.
The day lasts on average 15 hours and 40 minutes. So the days are long.
There are on average 8 hours of sunshine per day. So, the sun shines 52% of the time.
The average humidity is 83%. Hence, the air is normally humid.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 17 °C (62.5 °F). Therefore, the sea is cold for swimming.

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In August, the warmest month of the year, the weather in Guernsey is usually very mild. The average temperature is of 17.0 °C (63 °F), with a minimum of 14.1 °C (57.4 °F) and a maximum of 19.8 °C (67.7 °F).
On the coldest nights of the month, the temperature usually drops to around 11.5 °C (53 °F). However, it dropped to 10.3 °C (50.5 °F) in August 1993.
On the warmest days of the month, the temperature usually reaches around 25.5 °C (78 °F). However, it reached 32 °C (89.6 °F) in August 2020.
Precipitation amounts to 50 mm (2 in), distributed over 8 days.
The day lasts on average 14 hours and 20 minutes. So the days are long.
There are on average 7.5 hours of sunshine per day. So, the sun shines 52% of the time.
The average humidity is 84%. Hence, the air is normally humid.
The average wind speed is 17 kph (11 mph).
The average sea temperature is of 18 °C (64.5 °F). Therefore, the sea is cold for swimming.

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In September, the weather in Guernsey is usually very mild. The average temperature is of 15.6 °C (60 °F), with a minimum of 13.1 °C (55.5 °F) and a maximum of 18.2 °C (64.7 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 9.5 °C (49.5 °F). However, it dropped to 7.9 °C (46.2 °F) in September 2010.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 23 °C (73 °F). However, it reached 28.1 °C (82.6 °F) in September 2020.
Precipitation amounts to 60 mm (2.4 in), distributed over 9 days.
The day lasts on average 12 hours and 30 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 48% of the time.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 17 °C (62.5 °F). Therefore, the sea is cold for swimming.

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In October, the weather in Guernsey is usually mild. The average temperature is of 13.1 °C (56 °F), with a minimum of 11 °C (51.8 °F) and a maximum of 15.3 °C (59.5 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 7 °C (44.5 °F). However, it dropped to 3.5 °C (38.3 °F) in October 2003.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 19 °C (66.5 °F). However, it reached 22.2 °C (72 °F) in October 2011.
Precipitation amounts to 95 mm (3.7 in), distributed over 13 days.
The day lasts on average 10 hours and 40 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 35% of the time.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is 22 kph (13 mph).
The average sea temperature is of 15 °C (59 °F). Therefore, the sea is cold for swimming.

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In November, the weather in Guernsey is usually mild. The average temperature is of 10.2 °C (50 °F), with a minimum of 8.4 °C (47.1 °F) and a maximum of 12.1 °C (53.8 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 4 °C (39.5 °F). However, it dropped to -0.8 °C (30.6 °F) in November 2010.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 15.5 °C (60 °F). However, it reached 17.1 °C (62.8 °F) in November 2016.
Precipitation amounts to 105 mm (4.1 in), distributed over 15 days.
The day lasts on average 9 hours and 5 minutes.
There are on average 2.5 hours of sunshine per day. So, the sun shines 29% of the time.
The average humidity is 82%. Hence, the air is normally humid.
The average wind speed is 23 kph (14 mph).
The average sea temperature is of 13 °C (55.5 °F). Therefore, the sea is very cold for swimming.

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In December, the weather in Guernsey is usually quite mild. The average temperature is of 8.0 °C (46 °F), with a minimum of 6.2 °C (43.1 °F) and a maximum of 9.9 °C (49.7 °F).
On the coldest nights of the month, the temperature usually drops to around 1.5 °C (34.5 °F). However, it dropped to -1.8 °C (28.8 °F) in December 1991.
On the warmest days of the month, the temperature usually reaches around 13 °C (55.5 °F). However, it reached 14.4 °C (57.9 °F) in December 2015.
Precipitation amounts to 115 mm (4.5 in), distributed over 16 days.
The day lasts on average 8 hours and 10 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 2 hours of sunshine per day. So, the sun shines 23% of the time.
The average humidity is 83%. Hence, the air is normally humid.
The average wind speed is 25 kph (15 mph).
The average sea temperature is of 12 °C (53.5 °F). Therefore, the sea is very cold for swimming.