Hail is rain that falls as lumps of ice. Hailstones form in thunder clouds. If it is very cold, rain freezes. Then sleet may fall. A thunderstorm is a rainstorm with both lightning and thunder.
Thunderstorms begin in cumulus clouds.
Winds shake the moist air and raindrops fall. In a rainstorm, lightning may streak across the sky. Thunder is the sound caused by lightning. Air is heated instantly when light passes through it. Lightning is a giant electric spark.