Pull the light out of the niche.

The right way to winterize a wet-niche pool light is to physically remove it from the water and store it dry.

First, kill the power at the breaker, not just the switch. Then lower the pool water below the light niche if you haven’t already. You want the niche dry and the light out of the water.

Take out the screw or nut at the top of the light ring, pull the whole assembly out, and lay it on the deck. Coil the cord carefully so nothing kinks. Let the light air