Freezing point is an important quality specification for jet fuel. This is the temperature at which components in the fuel start to solidify into wax crystals.

Freezing point is measured as the temperature at which the last wax crystal melts when warming a fuel that has previously been cooled until wax crystals formed.

Freezing point specifications are a maximum temperature. A material with lower freezing point is more desirable. In general, low density (lower boiling point) material will have a lower (more desirable) freezing point.