Andreas Madsen

In my experience, the problem seems to be far worse in deep ocean biomes than in most other biomes.

UPDATE:
After using "--forceUpgrade --eraseCache" it initially didn't fix the problem. 
But a day and a few server restarts later, the problem seems to have gone away.
So I'm guessing eraseCache + a restart and some patience will solve the issue.

Alright, I've tried following the instructions for the "--forceUpgrade --eraseCache" thing.
I've tried it both through the control panel and by downloading the world and doing it in single player. 
The problem is still there.
[Edit] yes, I did use the world in 20w17a

I'm experiencing the same problem on my survival server.
It is not just the rain/snow though. 
Water won't freeze in the patches where is doesn't snow/rain.

I downloaded the server world and opened it in single player, and the problem still persists. 
I can not make it happen when I generate a new world with the same seed.

I find the problem with the weather in multiple different places in the problem world. 
I have not been able to figure out what the affected areas have in common. 

Is that enough info?

I haven't had the problem since I ran the "optimize world"-fix. 
(Side note: holy poop why are there so many status updates on this from the past hour? my email is getting spammed)

I experienced the same error, but was able to "fix" it by making a pillar of solid blocks that reached the sub-chunk above the the affected area. This caused the sky-light level to update.

I'm experiencing this on my small server world. 
It seems to happen pretty reliably when going back and forth between the nether and the overworld.

The world was created in an earlier 1.14 snapshot, but I can't remember exactly which snapshot it was.