The intensity of a tornado usually corresponds to the intensity of a severe thunderstorm. Since thunderstorms are convective storms, there is a dependence on solar heating. For that reason, tornadoes are most common in the late afternoon and evening. The sun heats the surface creating latent heat to supply fuel for massive thunderstorms. However, tornadoes can occur at any time of the day or night.
All 50 states have experienced tornadoes of differing severity. Typically, tornadoes will migrate in a more northward direction as spring progresses. In other words, more southern states experience tornadoes sooner than more northern states. The peak month for all states for the years 2003-2005 was May with June as a close second.
