The weather is maritime and quite changeable, from moments of brilliant sunshine, to misty hill fog, to showers. The Gulf Stream encircling the Islands tempers the climate. The harbours never freeze and the temperature in wintertime is very moderate considering the high latitude. Snowfall occurs, but is short-lived. The average temperature ranges from 3°C in winter to 11°C in summer. In sheltered areas, the temperature can be much higher, but the air is always fresh and clean no matter what the season.