What effect does altitude have on mexicos climate?

The higher the altitude the lower the temperature, and the lower the altitude the higher temperature

Mexico has a pretty rugged topography in such a way that its median altitude is on the 1,000-2,000 meter (3,000-6,000 feet) range.

This means although Mexico has an overall warmer climate than on the US, much of its territory is temperate and even cool, depending on altitude.

For instance, the northern city of Chihuahua has an average temperature of 17.8 °C (64 °F) and the southern city of Oaxaca has an average of 22°C (72 °F).