Thunderstorms

The figure above shows the average number of thunderstorm days each year throughout the U.S. (The graphic defines a day of thunderstorms as two lightning flashes within a 10 nmi (18.5 km) radius). The most frequent occurrence is in the southeastern states, with Florida having the highest number of "thunder" days (80 to 105+ days per year). This is because warm, moist air from the Gulf of Mexico and Atlantic Ocean (which we will see later are necessary ingredients for thunderstorm development) is most readily available to fuel thunderstorm development in this part of the country.