Although low temperature are the major characteristics of its climate, the Arctic is not always bitterly cold. During the summer, the temperatures over the Arctic Ocean are near 32°F. Winter temperatures, however, average between -22°F and -31°F. It is colder over land areas, especially over the Greenland ice sheet, where a winter temperature of -87°F has been recorded. In the subarctic, a region just south of the Arctic, winters are colder but summer are warmer. The lowest temperature ever recorded here was -90°F in Siberia. Like Antarctica, the Arctic receives little precipitation (rain or snow). The generally low temperatures limit the amount of moisture that can be held in the air and consequently the amount of snow that will fall. In March and April, when the greatest amount of snow covers the ground, the average depth in the Arctic is 8 to 20 inches. The snow, however, remains for 10 months of the year. The Arctic year is divided into a long, cold winter and a short, cool summer. Because of its geographical position, the Arctic is marked by long periods of darkness and daylight. At the North Pole the sun remains above the horizon for six months at a time and below the horizon for another six months, giving in effect six months of daylight, followed by six months of darkness.