Why is the weather in Nanchang so bad?

Surrounded by mountains, the terrain is low and opaque. Summer is sultry and winter is biting. As a person in charge from a neighboring province, these feelings do not come from weather data. For example, the rainfall is similar, but Nanchang is particularly uneven. Can be divided into dry season and rainy season. It rains every day in winter and spring, and it is damp and moldy. In July and August, it was hot and hot, and I was looking forward to rain and cooling down every day, but the rainfall dropped sharply and there was no rain. You can't go out for a few days all year round. Mainly it's basically boring. I feel that it is either dry steaming or wet steaming. As a foreigner, I haven't taken a few breaths of air comfortably without turning on the air conditioner.