(~50°C. in cooling from room temp.) The dry adiabatic rate of change in temp. with increase in elevation is -1°C. for 10,293 cm. This is often rounded off to -1°C. / 100 meters, or -5.4°F./1000 ft. The maximum effect of water vapor as a gas (un-saturated) [illegible] is to decrease the rate of cooling very slightly (~1 meter). Under saturated conditions, latent heat is released at condensation of water vapor (saturation adiabatic change). This adds heat to the dry adiabatic rate. As air rises, it expands and cools until saturation and finally condensation occurs. At that point, heat is released at condensation, so there is a slower rate of cooling with more expansion. Adiabatic heating and cooling is reversible as long as no water is removed from the air by condensation. If all the water vapor is removed by condensation, the air cools according to the dry adiabatic rate, so it returns to the surface at a higher temp. than when it ascended. The greater the temp., the more condensation can be released if the air is cooled. Example: cooling from 40°C. to 20°C. can release much more condensation than cooling from 20°C. to 0°C., even though the temp. difference is the same in both cases (it is not a straight line function). Lapse rate is the actual observed readings of temp. as altitude changes. It may or may not be the same as dry adiabatic rate. Lapse rate is considered positive if the temp. decreases with height. In the lower atmosphere the lapse rate usually but not always is positive. If temp. increases with rise in elevation, it