Synthetic wigs have a lot to recommend them. They hold their style, even if they get a bit wet in the pool or ocean. The fibers don't fade in the sun or turn colors. (But they can melt if you lean over an oven.)
While all wigs tend to be somewhat hot and itchy in the summer, lightweight synthetics are available. Their open-cap construction allows the head to breathe and heat to escape, so they're cooler to wear. Standard synthetics may be worn with a mesh wig liner that's like a fishnet stocking. This type of liner also helps keep your head cool.