Why do ordinary thunderstorms occur most frequently in the afternoon?

Answer 1

The temp of the air is at its highest around 3 pm (not noon as you may think). The warm air rises to meet the cold front and develops a storm system. Since this occurs in the afternoon, normal T'Storms arise in the afternoon. The exception, of course, is when a severe front moves through. The warm air will add to the fronts stability but not be the cause of the system itself.

Dr. Tommy Skelton

Answer 2

The maximum temperature of a particular day is usually recorded in the afternoon.So, the land is heated more at this time and the air above it also gets heated .This air rises due to buoyancy and thus strong convection currents are set up.Due to this, thunder clouds develop and thunderstorms occur mostly in the afternoon.