Louvered roof systems are provided with one or more louvers. Such louvers can be combined in an assembly that is movable between an open condition and a closed condition. In the closed condition, louvers in the assembly engage one another. In such engagement, a leg extending generally transversely from one louver may include a wing that extends generally transversely to the leg and that abuts a surface of an adjacent louver. Additionally or alternatively, in such engagement, a leg extending transversely from one louver may be received in a notch in an adjacent louver.