General Information Guernsey's climate is temperate - with the hottest months in August and September (with the temperature averaging 26 degrees Celsius). Conversely, the coldest month is February, where it has actually snowed on several occasions. However, the temperature rarely ever drops below zero. Guernsey's beautiful weather makes it the sunniest place in the UK - and boasts some of the most glorious sunrises and sunsets all year round, making it an ideal haven for escaping the dreary weather of London.