Why is it sultry and rainy?

Rainfall is generally affected by cold air and warm and humid airflow. It is caused by the same influence. The sultry weather is a sign of the increase of water vapor and temperature in the atmosphere, and it is also a precursor of thunderstorms in summer. The rain in summer is mostly showers and thunderstorms. The conditions for its occurrence are fine weather and high temperature in the early stage. The air has strong convection in some areas, which makes a lot of hot and humid air rise sharply, thus forming cumulonimbus clouds. At the same time, the hot air in the atmosphere increases and the water vapor is sufficient. The temperature doesn't change much at this time. There is a lot of water vapor in it, which tends to be saturated, making the water on the ground not easy to evaporate, and the sweat on people is not easy to volatilize, so it will feel boring and uncomfortable.