River biomes that run through mountains don't have snow at high altitudes

Unlike in the taiga biomes, which have frozen river biomes, normal river biomes that run through mountains don't have snow in higher altitudes. This leads to strange patches of rain amidst snow storms.

Example: Seed 8249540437131673049, /execute in minecraft:overworld run tp @s -880.92 106.26 21737.75 -491.85 34.65.