What is a " lightweight jacket"?

A lightweight jacket is a type of outerwear that is designed to be worn in mild weather conditions, providing a moderate level of warmth and protection from wind and light rain. It is typically made of lightweight and breathable materials such as nylon, polyester, or cotton, and is often unlined or lightly lined to keep the garment lightweight and comfortable to wear. The jacket can come in various styles such as the bomber, windbreaker, or track jacket, and can be used for various activities, such as hiking, running, or casual wear.