The melting point of water is the temperature at which it changes from solid ice into liquid water. The melting point for water is 0 degrees C (32 degrees F). The boiling point of water varies with atmospheric pressure. At lower pressure or higher altitudes, the boiling point is lower. At sea level, pure water boils at 212 °F (100°C). The boiling point of water also depends on the purity of the water. Water that contains impurities, for example, saltwater boils at high temperature than pure water.