Freezing Point of Seawater: Factors & Explanation

The freezing point of seawater is approximately -1.9 °C (28.4 °F). This is lower than the freezing point of pure water, which is 0 °C (32 °F). The reason for this difference is that seawater contains dissolved salts, such as sodium chloride (NaCl), which lower the freezing point of the water. The amount by which the freezing point is lowered depends on the salinity of the water. The more salt that is dissolved in the water, the lower the freezing point will be.