Quick update. Nice. I can indeed see the rain through the windows. Upon noticing the update, I gave it a try to see if the indoor weather would have been fixed, but unfortunately, it was not. It was, however, less visible indoors at night. So I decided to perform a few tests of my own during the day.
My beach house is located, well, on a beach, at the Y:60 level. A while go, I dug my own indoor mineshaft that went straight down on my property. That said, it's a long way up/down by ladder, and I also noticed there are no pre-generated caverns under the beach biomes. And yes, I can make a lot of glass now that we need sand. But I digress. Going down the ladder, I noticed the rain stopped at Y:-20, but if I climbed back up, the rain would resume just above Y:-20. Excluding the wooden rooftop above ground, that's an 80 level difference. Stacking layers of stone blocks above the roof didn't make a difference.
I then went to find one of the pre-generated mine located next to a mountain, and with the "setweather rain" command, I went in. I found that when I reached Y:0, the rain would stop. Jotting down the coordinates, I went above ground to the same X/Z coordinates, and found it to be Y:67, making it a 67 level difference.
I hope these tests can help you figure out the indoor rain problem, Red, but until the problem is fixed, it's good to know "setweather clear" will make the rain go away.
The fact that the rain ends after a certain depth is interesting enough. But can anyone else with a Mac who is having the same indoor rain issue, replicate this test?