There is no denying that a flannel shirt is the ultimate in warm winter clothing, but you can also get away with wearing it in the summer. Picture yourself at a beach or lake party on a hot summer's day. The party goes well into the night and being beside the water, you can feel a definite chill. This is where a flannel shirt can be your best friend. It is light enough to wear on a summer evening, but will still give you all the warmth you need. Teamed with a pair of cargo shorts or jeans and all you need under your flannel is a light t-shirt or tank top. A lightweight flannel shirt can also act as an excellent sun barrier, protecting your skin from the sun's harmful rays.