I would do this with policy and NAC. This would assume you have both available. The policy would be a deny all or could be deny some, allow other. The NAC would have a time group and location group defined. The time group would be the off hours/days you wish to restrict or deny access. The location group would define the access points/SSIDs or combination that you want to restrict or deny. A rule would be created in the NAC that would call the deny policy when the location and time groups condition are met. This not only accomplishes your immediate goal, but allows flexibility should your goals change, such as how much restriction to impose or different restrictions for different APs or SSIDs.