Windswept Hills seem to be considered a snowy biome by the game despite not having snow at all Y-levels

Windswept Gravelly Hills are very frequently generated in the middle of a snowy area, while not having any snow in it because it only starts to have snow at around Y-120
This seems to also be the case for the regular Windswept Hills but its more rare, and tends to generate a slightly larger area

Examples:

Seed: -7614548103003575706
Coordinates: /execute in minecraft:overworld run tp @s -3094.45 141.12 -3223.81 -38.72 34.00

Seed: 3518669480056999616
Coordinates: /execute in minecraft:overworld run tp @s 4386.11 128.64 714.46 -77.62 38.71

Seed: -6806120854195998574
Coordinates: /execute in minecraft:overworld run tp @s 3072.08 111.21 2723.90 182.02 33.48

Seed: -4345323682896242424
Coordinates: /execute in minecraft:overworld run tp @s 8322 112 5669 -1935 40.86

Seed: 2998013113788553796
Coordinates: At spawn