Lets say you have a chunk of cold air at sea level. The sun heats up the air near the ground by hitting the ground first(regular visible light just passes through the air instead of heating it). The increase in temperature causes it to expand(the weight of the air on top of you isn't changing, so the pressure stays the same for the moment.) Now your chunk of air is less dense than the surrounding gas, so it starts to rise.

The higher up you go the lower the air pressure, so your chunk of air expands even more, pulling heat out of the evaporated water it absorbed near the surface(which condenses into clouds and rain).

High up in the atmosphere it's cooled down a lot from expanding, but it still hasn't actually gotten rid of the energy it absorbed from that sunlight, it does this by radiating infrared light off into space, cooling off even more before it starts to sink back to the ground to start the process over.