No, it’s not really very cold, and it’s not really very hot, either. It all depends on where in the atmosphere you are!
The earth’s atmosphere consists of layers of gases. The lowest layer, called the troposphere, extends to a height of seven miles, and this is the layer in which all our weather takes place. In this layer, the air gets colder the higher you go, until it reaches a temperature of about 75 degrees below zero
But then, we enter the stratosphere, and in this layer the air gets warmer as you go higher! That’s because molecules of ozone gas in this layer absorb the sun’s heat. At the top of the stratosphere, about 30 miles above earth, the temperature is a comfortable 35 degrees.
As we rise above the stratosphere, the temperature begins to drop again, and at a height of 50 miles, reaches about 130 degrees below zero. But then the air starts getting warmer again as we climb higher.
A few hundred miles above the earth, the gas molecules may have a temperature of almost 2,000 degrees!