Home > Encyclopedia of Science > Thunderstorm

• How thunderstorms form
• Words to Know
• Lightning and thunder

A storm is any disturbance in Earth's atmosphere with strong winds accompanied by rain or snow and sometimes thunder and lightning. Storms have a generally positive effect on the environment and on human societies because they are the source of most of the precipitation on which the planet depends.

The most common violent change in the weather is the thunderstorm. In the United States, thunderstorms usually occur in the late spring and summer. Thunderstorms are rare in the parts of the country where the air tends to be colder, such as the New England states, North Dakota, and Montana. They also are rare by the Pacific Ocean, where summers are dry. The southeastern states tend to have the most thunderstorms. Some parts of Florida experience...