It's sultry in Longyao. Why doesn't it rain?

Generally, summer rainfall is caused by the combined influence of cold air and warm and humid airflow, and the sultry air is a sign of the increase of water vapor and temperature in the atmosphere, and it is also a harbinger of the coming thunderstorm in summer. Most of the summer rains are showers and thunderstorms, which are due to the fine weather, high temperature and strong convection in some areas, which makes a large number of hot and humid air rise sharply and form cumulonimbus clouds. At the same time, there is more hot air and a lot of water vapor in the atmosphere. At this time, although the temperature has not changed much, it tends to be saturated because there are many water vapor in the atmosphere, which makes the water on the ground not easy to evaporate and the sweat on people not easy to volatilize, so it will feel very stuffy and uncomfortable. This is because the air pressure began to drop. A large number of ions have accumulated in the air.