Just in case this wasn’t clear from the other comments, basically the answer is, it doesn’t matter that much. I have dozens of extensions cords plugged into each other just sitting in the rain and snow, it’s never been a problem.

Should I worry about it? Yeah probably. It’s good you’re worrying about it. Just don’t aim for perfection. If you start thinking about it like “if a drop of water falls in here it’ll be a crisis” you’ll drive yourself crazy. Take a few reasonable precautions and remember that I had a full power strip, facing up that I forgot to tuck under the deck, powering a few hundred watts of Hue outdoor lighting that was just sitting in the rain for a week before I noticed, and it was fine. Do better than I do, but remember that water is WAY less conductive than people think. (Perfectly distilled water is actually not conductive at all. You could cut the end of an extension cord, hook it up to 277v power and drop it in a bathtub you were in and you’d be fine so long as you were in distilled water. Though don’t test that)