What season do most tornadoes most occur?

It actually varies with region, with the deep south and down toward Florida getting their season in late winter/early Spring, while the upper Midwest has their tornado season during the Spring and Summer. Tornadoes are most common in general from the months of April through June, which corresponds to tornado season in much of tornado alley through the Ohio River Valley.

However, tornadoes can (and have) occurred any day of the year.