Powder snow is supposed to do that, it's not very common though.
For now I managed to find a grove biome where I actually sank in just once.
A certain idea came to my mind - making leather possible to combine with chainmail to get iron armor level of protection, at lowered durability and enchantability.
Leather-based armors could also have an effect of reducing player's visibility to Strays (that act as ice elementals of sorts) or alternatively to mobs that specifically see in infrared since leather armor is supposed to insulate the player thermally. Every piece would stack up and make you better insulated and more blending in with the environment.
Besides preventing players from being in permanent Slowness status after suffering hypothermia according to the suggestion I made to make climate matter in Minecraft, leather armour could be made to have additional benefits, I agree. Hypothermia could be made to kill players directly but only in cold water without enchantments or in hardcore mode, I feel it killing players just for existing in a Snowy biome would be hated if it were enabled on lower difficulties.
Perhaps wearing leather armour could be used to make Strays neutral until they are attacked by players or if a player aims a bow at them.
And in Ice Spikes and tundra biomes leather armour can protect players from freezing temperatures and would mean they wouldn't have to use a campfire or fireplace to warm themselves up to eliminate Slowness status every time they were in an Ice biome.
Then having leather armour in trades makes a lot of sense,
Besides preventing players from being in permanent Slowness status after suffering hypothermia according to the suggestion I made to make climate matter in Minecraft, leather armour could be made to have additional benefits, I agree. Hypothermia could be made to kill players directly but only in cold water without enchantments or in hardcore mode, I feel it killing players just for existing in a Snowy biome would be hated if it were enabled on lower difficulties.
Perhaps wearing leather armour could be used to make Strays neutral until they are attacked by players or if a player aims a bow at them.
And in Ice Spikes and tundra biomes leather armour can protect players from freezing temperatures and would mean they wouldn't have to use a campfire or fireplace to warm themselves up to eliminate Slowness status every time they were in an Ice biome.
Then having leather armour in trades makes a lot of sense,
since it's no longer useless late game.