The lapse rate of the atmosphere is

The lapse rate is the decrease of an atmospheric variable with an increase in altitude and when the variable is not specified it is taken to be temperature.

🔑Key Points:
-The lapse rate of non-rising air is commonly referred to as the normal, or environmental, the lapse rate is highly variable, being affected by radiation, convection, and condensation.
-The atmospheric temperature in this layer decreases at the rate of 1ºC for every 165m of height.
-This decrease in air temperature with altitude is because air is compressible and the density of the air decreases with altitude.
-It averages about 6.5 °C per kilometer (18.8 °F per mile) in the lower atmosphere (troposphere).
Hence, the lapse rate of the atmosphere is 1°C per 165 meters of ascent. This is known as the normal lapse rate.