The stratosphere is where you'll find the very important ozone layer. The ozone layer helps protect us from ultraviolet radiation (UV) from the sun. In fact, the ozone layer absorbs most of the UV radiation the sun sends to us. Life as we know it wouldn’t be possible without this layer of protection.High-altitude locations isusually much colder than areas closer to sea level. This is due to the low air pressure. Air expands as it rises and the fewer gas molecules including nitrogen, oxygen, and carbon dioxide have fewer chances to bump into each other. Temperature increases in altitude within the stratosphere because of the ozone layer which traps much of the sun's radiation from traversing into lower regions. The ozone layer is comprised of ozone molecules that capture ultraviolet rays from the sun.

In the high mountains, there is neither water vapor nor dust particles. So there is unchecked radiation. That is why the mountains are cooler than the plains. High altitudes have lower atmospheric pressure as compared to the plains. Low atmospheric pressure contributes to low temperature. Therefore, high altitude areas have low temperature when compared to the plains. This happens because as altitude increases, air becomes thinner and is less able to absorb and retain heat. The cooler the temperature the less evaporation there is, meaning that there is more moisture in the air.High-altitude locations are usually much colder than areas closer to sea level. This is due to the low air pressure. Air expands as it rises and the fewer gas molecules including nitrogen, oxygen, and carbon dioxide have fewer chances to bump into each other. As air rises, the pressure decreases. It is this lower pressure at higher altitudes that causes the temperature to be colder on top of a mountain than at sea level. The denser, cooler air on mountain-tops sinks into valleys, and collects there. Second, over the course of the night, the valley begins to fill from the bottom with cold layers of air. Temperatures drop as you move upward through the troposphere. The temperature drops about 6.5° C with each increase in altitude of 1 kilometer. The rate at which the temperature changes with altitude is called the "lapse rate". Heat is produced in the process of the formation of Ozone and this heat is responsible for temperature increases from an average -60°F (-51°C) at tropopause to a maximum of about 5°F (-15°C) at the top of the stratosphere. It is the lowest layer in the atmosphere and extends upwards about 10kms above sea level starting from the ground. It contains 75% of all air in the atmosphere. Generally, the temperature decreases with increase in height because the atmosphere distributes itself according to gravity. At the top of the stratosphere (about 50 km, the stratopause), the temperature begins to decrease again as the altitude increases. Above the stratopause, in the mesosphere, thermosphere, and exosphere harmful gamma rays and X-rays are absorbed. Air is warmest at the bottom of the troposphere near ground level. Air gets colder as one rises through the troposphere. That's why the peaks of tall mountains can be snow-covered even in the summertime. Air pressure and the density of the air also decrease with altitude.