The Faroe Islands are an archipelago between the Norwegian Sea and the North Atlantic Ocean. The terrain is rugged; the climate is subpolar oceanic with windy, wet, cloudy, and cool weather. Temperatures average above freezing throughout the year, hovering between 12 °C (54 °F) in summer and 5 °C (41 °F) in winter. The northerly latitude location also results in perpetual twilight during summer nights and very short winter days. Settlers introduced grass roofs to their shelters as an effective protection from the rain and cold.