Convectional rainfall is very common in areas where the ground is heated by the hot sun, such as the Tropics.
The sun heats the ground and warm air rises.
As the air rises it cools and water vapour condenses to form clouds.
When the condensation point is reached large cumulonimbus clouds are formed.
Heavy rainstorms occur. These usually include thunder and lightning due to the electrical charge created by unstable conditions.