Although each region has a rainfall pattern that depends a lot on its geography, rain tends to be more frequent in the morning and afternoon than at night.
For clouds to form, a humid air mass must rise, expand, and cool; and that the vapor that is thus formed, condenses. Updrafts arise for four reasons: a low pressure atmospheric zone; an obstacle that forces the air to rise; the collision of a cold and a warm air mass and; finally, the rise by convection of the air in contact with the surface, which is hotter than that of the upper layers. The first three situations can occur at any time, but convective currents are typical of the day, when the sun has heated the ground for hours.
