where on mars is the coldest north or south?

Answer 1

The south pole on Mars has colder winters than the north pole, because Mars is furthest from the sun during southern winter. This is reflected in the south polar cap being larger and having a layer of perpetually frozen carbon dioxide. The north pole gets a carbon dioxide cap in the winter, too, but it evaporates in the summer.

Answer 2

The poles are colder than the equator, like on Earth. Except on the poles of Mars in the winter, the "snow" is not water ice, it's carbon dioxide ice. Bbbbbrrrrrrrrrrrr!!!!

By Earth standards, it always cold, everywhere on Mars.