I made the color scheme of desert large and it's better. But even with that 95% of the north est steppe remain a steppe. I guess there is not much I can do but accept reality. The cold deserts cover almost twice as much land in the large continent and the high plateau of the northern continent. Hot deserts now appear on some mid latitude island near the tropics , in the central continent and made the one large desert a little larger.

I moved the coldest Ca to the Cb: now we have a transition between Ca and Da. It's close to the 30th parallel at some places but I think it's ok. This has no impact on the biome.




Now unless someone spot something that doesn't make sense, I will consider my method acceptable (but I still need to find the missing colors).