The rain keeps falling inside the house.  Does anyone know if there is a way to fix it?

Thats odd. The rain shouldn't Rain inside the house. 

Try any of the following methods:

1) Turn off Rain FX under Options and Restart the game

2) If No.1 doesn't works then backup your save file and reinstall the game

Your Save File is located in:

C:\Users\(Your Name)\AppData\Local\Shopsim\SaveGames\

There are 2 files, one is the settings and the other is the save data. Copy both of them.

3) Try making a new game... Starting a New Game most probably fixes all the bugs but loses your data. I had a couple of bugs too but when I started new game they all fixed ;D

I've had rain issues before too - right now its working properly My assumption is that its all based on whether the game decides if its raining or not upon reload. - The rain initializes... afer? the house has been initialized?

I dunno. See. It's lightly sprinkling/raining right now, right right now, in my game - it wasn't raining when I started this session/reload

As soon as I stepped on my house's platform, the rain ceased being visible - Like I couldn't even see any droplets off out at the edge of yard, making me think it'd stopped raining just as I was testing it.

There was a brief delay as I walked off the platform, but then I could see rain again.

I think when you reload, and I dunno if it remembers raining trigger or if it rolls every time it reloads and every other random time that it occurs....

but I think if when you reload - it was raining during reload - it'll break through the house

I don't know if it'll stay until the next save and reload (potentially when no rain)

or if maybe changing to the cave would solve the issue  - as the house-platform is supposed to trigger a cease, apparently.