Rain gets stuck on despite sleeping on my single player world until I close the game and reopen.  I believe its a visual bug, as hostile mobs usually spawn under some trees during rain, but none have.  Four strait days of rain.  Along with this, right before the most recent hotfix (1.17.40) the sky got stuck on gray skies (not in or near a desert) when I came out of a nether portal for several game days until I closed and reopened- it was not raining.