Melting point is the temperature at which a solid melts to become a liquid. Since water is already a liquid, it does not have a point at which it liquefies. Frozen water is called ice and has a normal melting point of zero degrees Celsius, according to Purdue.
Liquids have a point at which they turn into a solid, which is called a freezing point. Theoretically, the freezing point of a liquid is the same as the melting point of its solid version. When nucleators are absent in water, it can be supercooled to -42 degrees Celsius before freezing. Supercooling is a process that lowers the temperature of a liquid below the normal freezing point without transforming to its solid state.