Changing weather to clear, in a custom overworld biome dimension does not change at all, the other overworld words need to be changed inorder for it to work
Let's say you have two custom worlds, of type "minecraft:overworld", and try to change the weather, it won't change, you need to go to the main overworld and change it there aswell, for some reason.
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We're tracking this issue in MC-186626, so this ticket is being resolved and linked as a duplicate.
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