The islands have an Antarctic climate, tempered by their maritime setting. The weather is marked by low seasonal and daily temperature ranges, persistent and generally low cloud cover, frequent precipitation and strong winds. Snowfall occurs throughout the year. At Atlas Cove (at the northwestern end of Heard Island) the monthly average temperatures reported lie in the range from to . The average daily variation of temperature is from to in summer and to in winter. The winds are predominantly westerly and persistently strong. At Atlas Cove, monthly average wind speeds range between around . Gusts in excess of have been recorded. Annual precipitation at sea level on Heard Island is in the order of ; rain or snow falls on about 3 out of 4 days. The Relative Humidity also remains high at more than 80% through most of the year and this condition coupled with mountainous terrain results in high cloud cover and often-spectacular cloud formulations, such as cap, lenticular and rotor (collectively wave clouds) commonly observed over and downwind of Big Ben and to a lesser extent Laurens Peninsula.