Understanding these clues can be the difference in getting to safety in time when weather suddenly turns for the worst. Basic Facts about Thunderstorms Thunderstorms occur in all 50 states. They can occur, at any time, day or night, throughout the entire year. Thunderstorms are most common in the late afternoon and evening during the warm months. Approximately 1800 thunderstorms are in progress at any given moment around the world and lightning strikes the earth 100 times every second.
Thunderstorms are basically beneficial providing necessary rainfall.
In the United States, only about five percent of thunderstorms become severe and only about one percent of thunderstorms produce tornadoes. The sun warms the ground and the ground warms the air above it. Evaporation of moisture from the ground or bodies of water increase the humidity. The warming of the air and the increase in humidity cause the air mass to destabilize. If there is cooler, drier air above, the tendency would be for the air to want to overturn with the cooler air sinking and the warmer air rising.