There are generally two types of tundra, the arctic tundra, and the alpine tundra. They both share the characteristics of being cold and dry. Of the two, the Arctic Tundra is by far the largest, covering 1/5 of Earth's land surface.
With temperatures as low as -57°C (70°F), and winds that can reach 161kmph (100 mph), life is very harsh. In these conditions, water freezes, providing conditions similar to a dessert, except that it is cold instead of hot.
Tundra seasons are extreme. During the short summer, the tundra's water
unfreezes, providing a short time of plant growth. During this time, hibernating
animals come out to hunt, and have a short mating season.