A. Because the water around the island absorbs the extreme heat of summer, and gives out heat to mitigate the extreme cold of winter.
Q. Why does the sea round an island give out heat in winter?
A. Unless the sea be frozen (which is rarely the case), it is warmer than the frozen land; and, therefore, the warmth of the sea air (mixing with the cold land air) helps to mitigate the intense cold.
Q. Why are there waves in the sea?
A. The wind (acting on the surface of the sea) piles up ridges of water, which leave behind an indentation: as the water on all sides rushes to fill up this indentation, the disturbance spreads on all sides, and billow rolls after billow.
Q. Why does wind in England generally feel cold?
A. Because a constantly changing surface comes in contact with our body, to draw off its heat.
Q. Why is a room (even without a fire) generally warmer than the open air?
A. As the air in a room is not subject to much change, it soon becomes of the same temperature as our skin, and no longer feels cold.