This simple TPU sleeve provides basic environment resistance for cauldron light. I bought mine from Aliexpress, but also the one from Maker's Supply is the same.

If you want to add extra water resistance, you can glue the sleeve to seal it. But I didn't test it and I do not guarantee that it will work.

You can control switch through sleeve - in such case put the sleeve on light when the light is turned on. It is beacuse it is difficult to move switch when the sleeve is on, you can move it only a bit and it is easier to turn off the switch from turned on state.