Belle Isle has a marginal subarctic climate (Köppen climate classification Dfc), exceptionally cold for a coastal location so far south as the 51st parallel. As an illustration, Dunkirk on the opposite side of the Atlantic averages warmer for the year as a whole, due to the contrasting currents on the eastern and western sides of the Icelandic Low. The climate features short, cool summers and long, severely cold winters lasting most of the year. Precipitation peaks during the warmer months of June to September in the form of rain.
