When many meteors fall through the atmosphere in a short time, the event is called a meteor shower.

Meteor showers are formed mainly by comets that come too close to the sun. Heat from the sun causes dust and rock to break off the comet's nucleus, and this gathers into a collection of debris that continues to move along the comet's orbital path. If Earth's orbit crosses this path, the dust particles burn up in the atmosphere to produce a meteor shower about 90 kilometers (56 miles) above Earth's surface.

Each meteor shower happens on roughly the same date each year, as Earth passes again through the same comet's debris trail.

There are about a dozen major and many more minor showers throughout the year—the most famous are the Leonids, the Geminids, and the Perseids. Some meteor showers are spread out over a few weeks, while others are highly concentrated, with most of the meteors striking the atmosphere within a few hours. Some showers (particularly the Leonids) vary greatly in intensity from year to year.