The weather is sultry. Why is the ground wet?

Summer rainfall is generally caused by the combined influence of cold air and warm and humid airflow, while sultry is the expression of the increase of water vapor and temperature in the atmosphere. This is also a precursor to thunderstorms in summer. The rain in summer is mostly showers and thunderstorms, which is due to the fine weather, high temperature and strong air convection in some areas, which makes a large number of hot and humid air rise sharply and form cumulonimbus clouds. At the same time, the hot air in the atmosphere is increasing and the water vapor is rich. At this time, although the temperature has not changed much, it tends to be saturated due to a large amount of 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.