There are two main seasons, winter and summer, in the polar tundra areas. During the winter, it is very cold and dark with an average temperature of around -28*C and sometimes going as low as -50*C. In the summer, the sun is in the sky 24 hours a day. This sun only warms the arctic tundra to a range of about 3*C to 12*C. The winter, however, is very cold. There are several weeks where the sun never rises and this causes the temperature to drop to extremely cold levels. It can sometimes get as cold as -70*C!
Percipitation in the arctic tundra is very minimal. They get around 15 to 25 centimeters of percipitation per year. Most of it is snow, because it is so cold. This biome is often refered to as a cold desert because of its lack of percipitation. Even with the lack of percipitation, there is a lot of standing water called permafrost. Each summer, the upper layer of the ice melts just enough to make small pools of water. The permafrost blocks the water form soaking into the ground, though, so these pools will freeze in the winter and the cycle repeats itself every year.
Percipitation in the arctic tundra is very minimal. They get around 15 to 25 centimeters of percipitation per year. Most of it is snow, because it is so cold. This biome is often refered to as a cold desert because of its lack of percipitation. Even with the lack of percipitation, there is a lot of standing water called permafrost. Each summer, the upper layer of the ice melts just enough to make small pools of water. The permafrost blocks the water form soaking into the ground, though, so these pools will freeze in the winter and the cycle repeats itself every year.