Step-by-step explanation:
Our atmosphere has different layers. The lowest layer is called as troposphere which extends up to 10 - 20 km from the surface depending on where you are on Earth. Most of the weather phenomenon occur in this region only. As we go to higher altitude in this region the temperature decreases at a rate of around 6.5 C per km.
The second layer above this is known as stratosphere which extends up to around 50 km from the surface. This part contains most of the ozone layer. Ozone layer is responsible for protecting us from UV radiation from the Sun. This layer absorbs the UV radiation thus the temperature in this layer increases with altitude.