1. Keep your body temperature: jogging will warm your body and cause sweating. However, when the body loses too much heat, the body temperature may drop, leading to colds or other health problems. A thin coat helps to keep your body warm and avoid excessive heat dissipation.

2. Sun protection: In summer, the radiant heat of the sun may cause sunburn and other health problems. A thin coat can help block the radiant heat of the sun and provide additional sun protection.

3. Protect the skin: Ultraviolet rays in the sunlight in summer may cause damage to the skin, increasing the risk of skin aging and skin cancer. Wearing a light coat can provide a layer of protection and reduce the direct exposure of the sun to the skin.

4. Personal habits and preferences: Some people feel more comfortable or confident when jogging, especially when others are present. Wearing coats may be just their personal habits or preferences.

In short, although jogging in summer may add some discomfort, for some people, it is a way to help them stay healthy and comfortable.