Average precipitation levels in polar climates are very low. Rainfall is normally below 10 inches per year in polar tundra climates and can be as low as 4 inches near the polar ice caps.
Thick snow and ice in many parts of polar regions can be deceiving. While it might appear that such landscapes would have high precipitation, in actuality many polar climates are more akin to deserts. This is because polar climates are dominated by very descending cold air masses that lack moisture, thus preventing the formation of clouds. In fact the large continental ice sheets of Greenland and Antarctica have taken millions of years to form and are not a product of recent heavy snowfalls.
While the polar tundra climate is slightly wetter than that of the poles, polar tundra can also be classed as a desert. The wet soils of the tundra can be misleading. The moisture in the ground is typically a product of permafrost melting due to slightly warmer summer temperatures rather than of rain. Although it is well-known that polar climates have low precipitation, data on detailed variations is scarce. Meteorological stations struggle to acquire accurate measurements in Arctic conditions and as a result, little information exists about the impact of regional differences in altitude and topography.