Which face of the mountain is typically warmer?
East or West

This is often the eastern side of the mountain range because prevailing winds in the mid-latitudes blow from the west, but that is not necessarily always the case. In contrast to the moist windward side of a mountain, the leeward side typically has a dry, warm climate.

west

Explanation:

In temperate regions mountain slopes facing the Equator—southward in the Northern Hemisphere and northward in the Southern Hemisphere—are significantly warmer than opposite slopes.