“Lining” refers to the smooth, silky fabric that can be found on the inside of suit jackets or sportcoats. Lining serves several purposes: its slick surface prevents shirts from getting caught on the fabric of the jacket, and the layer it creates between shirt and suit protects the latter from perspiration. And with customization, choosing the color of your lining is just one more way to inject personality into tailored clothing.
So, there are definite advantages to having your jacket lined. But once temperatures begin to rise, you may want less of it.
An excellent compromise is what’s called “half-lining.” This technique retains lining on the sides, the upper back, and in the sleeves, but leaves most of the back unlined. This way, the areas that are most likely to cause friction with your shirt (sleeves, shoulders) or perspiration (underarms) are still covered, but the totally unlined back becomes more breathable and better promotes airflow, helping you stay cool.
A jacket made from any type of fabric can be half-lined, but when combined with an already breathable, lighter-weight fabric such as linen, cotton, or seersucker, you can end up with one seriously cooled-down look.