Most violent tornadoes (F4 and F5) occur in the months of March-June.
Violent tornadoes have been recorded in most states east of the Rockies. However, most of the violent tornadoes occur on the Great Plains in the central part of the country.
A tornado anywhere is a violent event. If you mean by the technical definition of a violent tornado, one rated EF4 or EF5, such tornadoes do occur fairly regularly in Tornado Alley, but make up a very small minority of the tornadoes that occur there. As with most places, most of the tornadoes in Tornado Alley are rated EF0 or EF1.
The year with the most violent tornadoes on record was 1974, with a total of 36 tornadoes rated as violent.
Violent tornadoes (those rated F4 and F5) most often strike in late spring or early summer. However, they can occur at any time of year.
Weak tornadoes (EF0 and EF1) are by far the most common accounting for 89% of all tornadoes. Strong tornadoes (EF2 and EF3) are next, accounting for about 10% of tornadoes. Finally come violent (EF4 and EF5) tornadoes, which account for less than 1% of all tornadoes.
Most tornadoes occur in spring.
Tornadoes
Although tornadoes occur in all states, the state with the most tornadoes is Texas.
Most tornadoes occur in spring and summer.
Tornadoes most often occur in the spring an early summer as that is when the collisions of air masses of different temperatures and dew points are most violent and most like to produce severe thunderstorms.
The most violent winds on Earth are found in tornadoes.