Overall, humidity in the Arctic atmosphere is low. In some places, Arctic air is as dry as air in the Sahara desert. Humidity tends to be higher over the oceans and in coastal areas in summer, when water vapor evaporates from the relatively warm ocean surfaces. Humidity is lower over land areas, such as Canada, where there is less water to evaporate. In winter, humidity is very low because surface temperatures are very cold and very little water evaporates into the atmosphere. At this time of year, sea ice covers much of the Arctic Ocean, preventing evaporation from ocean water. However, in areas where there is no sea ice cover in areas, there can be a lot of evaporation and fog can form, making the ocean look as if it is steaming