What is the hottest and coldest part of the Earth's Atmosphere?

What is the temperature of the atmosphere?The mesosphere starts at 50 km and ends at 85 km high.The temperature at the top of the mesosphere is minus 130 degrees F.It's hard to study this layer.

The mesosphere extends above the stratosphere.The lowest part of the atmosphere can reach 90C.The air is thin in the fourth layer of Earth's surface, the thermoosphere.