what y coord do slimes spawn on minecraft pc
Apart from spawning in swamps (added in 1.4), slimes can only spawn in every 10th chunk in average (Slime Chunks). Chunks are 16x16 blocks wide (x and z axis) and 256 blocks high (y axis). Slime Chunks are predetermined by your savegame seed, and are always the same for a specific seed, just like the generated terrain.