Hailstones form when tiny particles are swept via updraft high into a storm system and coated with ice. These small hailstones may be lifted into the storm repeatedly, where they continue to grow in size before finally falling. Hail can occur in any season, but different regions of the United States experience hail at different times of the year.
Late Winter and Spring
East of the Great Plains, hail activity is most prevalent in spring. The southern states of the region are most vulnerable to hailstorms in March, while the northern states experience a hail season in May. The U.S. West Coast experiences peak hail activity during late winter and spring.
The leeward or windy side of the mountains on the Great Plains may see a few hailstones during the spring. In this region, though, hailstones fall more often during the summer.
The only region that experiences a hailstorm season in the fall is the Great Lakes area of the Midwest. Hailstorms may also occur during others seasons in the Midwest in the presence of cold thunderstorms, where the ground is still warm.