The Scratch Cats will tell you the temperature at the height of a mountain based on the mountain's height and the temperature at the base of the mountain. The one on the left is correct. This is a school thing. Temperature decreases by 1 degree Celsius every 100 meters for the first 900 meters (measured from the base of the mountain). From there on, the temperature decreases 0.6 degrees Celsius every 100 meters.