When rain is falling outside it is not blocked by solid blocks overhead. This includes several floors of above ground build and underground in caves or a mine.
MC-193864
Rain falling inside
Resolved
Duplicate
0
Hi there!
This looks like a duplicate of MC-179845. On that bug report, there is a moderator note that tells you how to fix the bug. If you opened this world in 20w17a, then this is the bug you're seeing here.