The boiling point corresponds to the temperature at which the vapor pressure of the liquid equals the surrounding environmental pressure. Thus, the boiling point is dependent on the pressure. ... At higher elevations, where the atmospheric pressure is much lower, the boiling point is also lower.

How is boiling point related to atmospheric pressure?

The boiling point of a liquid is directly affected by atmospheric pressure. This is the pressure exerted by the weight of the air molecules above the liquid. In an open system this is called atmospheric pressure. The greater the pressure, the more energy required for liquids to boil, and the higher the boiling point.

Why does atmospheric pressure affect boiling point but not melting point?

Because the atmospheric pressure is lower, the vapour pressure of the liquid needs to be lower to reach boiling point. Therefore, less heat is required to make the vapour pressure equal to the atmospheric pressure. The boiling point is lower at higher altitude.