Certain Windswept biomes (and Taigas) are inconsistently snowing and raining in random spots even at the same Y-level

Windswept Hills, Windswept Gravelly Hills and Windswept Forests have random patches of snowing spots on the same Y-axis instead of being fully covered in snow, or having no snow at all.

Taigas have the same issue if they generate on a very high Y-axis, but it's more rare. It can be however observed if the player flies or builds higher than the terrain is.

Example:

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/execute in minecraft:overworld run tp @s -1954.48 122.66 546.25 109.22 26.61