Guernsey, where it is located

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 6.5 °C (43.5 °F) in February to 17 °C (62.5 °F) in August. Here are the average temperatures.
Guernsey - Average temperatures
Min (°C)54679121414131186
Max (°C)9810121518202018151210
Min (°F)413943454854575755524643
Max (°F)484650545964686864595450

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.
Guernsey - 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 freezing. However, the cold records are around -6/-7 °C (19/21 °F).

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. Hot days are rare: the temperature may never reach 25 °C (77 °F) for an entire month. However, the highest records are 32 °C (89.5 °F), set in July 2019, 33 °C (91 °F), set in August 1990, and 34 °C (93.5 °F), set in August 2003.

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.

St. Peter Port

The sun in Guernsey is rarely seen from October to March, while from April to September, it shines for an acceptable number of hours. In one year, there are 1,865 hours of sunshine. Here are the average sunshine hours per day.
Guernsey - Sunshine

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.
Guernsey - Sea temperature
Temp (°C)1099101214171817151312
Temp (°F)504848505457636463595554

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.