The higher into the atmosphere you go, the cooler it becomes. This is because at higher elevations there is a lower air density that allows infrared bouncing from the earth surface to escape to space – because they collide with fewer air molecules than in the lower atmosphere.
Higher elevated areas- like mountainous regions- are also more likely to receive rainfall than low elevated areas. This is because they force warm moist air into the cooler upper atmosphere where the moisture condenses and precipitates.