Hail is a type of precipitation that consists of balls or irregular lumps of ice, known as hailstones. It forms in strong thunderstorms when updrafts carry water droplets high into the atmosphere, where temperatures are below freezing. These droplets freeze and can be lifted multiple times, accumulating layers of ice before falling to the ground. Hailstones can vary in size, from small pellets to larger stones that can cause significant damage. They are most common in the spring and summer months, particularly in regions prone to severe weather, such as the Great Plains in the United States.