The Western Cordillera has the highest elevation out of any part of Canada. At higher elevations, air molecules are spaced farther apart, meaning the air is less dense. The air is less able to trap heat from the sun, so temperatures are cooler.
The Interior plains have the lowest elevation out of any part of Canada. At lower elevations, air molecules are closer together, meaning the air is more dense. The air is better able to trap heat, so temperatures are warmer.
