I found this product at the feed store one day when we stopped by to pick up chicken feed. It's made for all sorts of outdoor electrical cord connections and is an excellent choice for your male-female cord connects if you are concerned about environmental exposure.
Here is a quick video review! I give this product a thumbs up for light rain and snow when used with medium and heavy-duty extension cords. Not really as useful with Christmas tree lights with smaller gauge wiring.
Just google "cord connect" to see where you can find them online.