Special weather phenomenon, please explain, thank you.

Because the atmospheric temperature is inherently high in summer.

The weather is fine before noon.

Water vapor evaporates rapidly with the rise of hot air.

The continuous evaporation of water vapor meets condensation at high altitude to form cumulonimbus clouds (which can also be called convective clouds at this time), often in the afternoon.

Cumulonimbus clouds accumulate and eventually form heavy rain or hail when the hot air below can't support them.

Often the higher the ground temperature, the greater the rain or hail!

This phenomenon is very common in tropical rainy season and temperate summer, so it is not very special.