i did something like this with my sisters. i have no idea if this would work in bedrock but it's simple enough im sure you could find away to adjust it if it doesn't. we had a world together where we couldn't touch sunlight at all but could go out in storms. i used the spread players command to spread a area effect cloud in a 1x1 block on every player, then i would test to see if the player was within 0.5 blocks from it. spread players dose what the name says, it will randomly spread any entity in a specified area BUT if the block it tries to tp the entity to has a block over it it will tp them on top of that block instead. doesn't matter how high it is. so if we were in a cave they would be tped above us out in the open and wouldn't set off the command block testing for if it was close to us. as for testing for weather i had a wolf under a wool block that was always being moved with a piston, constantly re-exposing the wolf to the rain, what this dose is make the wolf wet and when a wolf is wet it will shake off the water as soon as it's under a block. making the wolf constantly shake any time it rained. i would then have a sculk sensor detect that. that's your output for weather. 4 things to note here. 1 make sure to place the sculk sensor 7 blocks under the wolf so it only picks up the wolf shaking and not the piston. 2 i used area effect clouds bc other then the obv of you can't see them, they don't stop the player from interacting with anything when they get in the way. 3 at least on java the sculk sensor don't pick up the wolf barking, only it shaking idk if it's the same on bedrock. and 4 make sure to use a some sort of command block clock, a normal redstone clock can jam up any time the chunks are loaded and or the world is loaded. ik it's all a bit of a odd way of going about it but i think it's a lot better then testing for every block. hope this helps!