You can use a cover for your pool anytime you want. During the summer if you have the patience to cover it each time you are not using it, that is great. They are terrific safety measures that can be taken to protect kids and pets. If you know that you will be out of town for a while or on vacation and away from the home, then it is a terrific idea to cover the pool securely. Pools can be covered for other reasons as well, such as during the fall when leaves from trees tend to fall and cause huge problems with cleaning a pool. Covers are for any time that you feel the need to keep things out and safe.