What happens to temperature and pressure when altitude increases?

temperature decreases and pressure also decreases

Explanation:

Temperature - As you increase in elevation, there is less air above you thus the pressure decreases. As the pressure decreases, air molecules spread out further (i.e. air expands), and the temperature decreases. If the humidity is at 100 percent (because it's snowing), the temperature decreases more slowly with height.

Pressure - As altitude rises, air pressure drops. In other words, if the indicated altitude is high, the air pressure is low. This happens for two reasons. ...As altitude increases, the amount of gas molecules in the air decreases—the air becomes less dense than air nearer to sea level.