As stated above, when you use a 1.17 client to play in a 1.18 server, it will cause rain to appear in snowy and dry biomes if there is a cave biome underground.

To reproduce:

1. Join a 1.18 server that has rain enabled using a 1.17 client.
2. Locate a snowy (snowy taiga, ice spikes, etc.) or dry (desert, savanna, etc.) biome that has a cave biome (lush caves or dripstone caves) underneath it.
3. Wait for it to rain.
4. When it rains, observe the type of precipitation and compare it with the surface biome.
   → It will rain when it should be either snowing or not raining.

I suspect that this is a client-side problem because weather works normally when you use a 1.18 client to access the server and because the rain resulting from this bug does not make any sound.