At what temperature does water freeze?

32°F or 0°C or 273.15 K

Pressure has an effect on the freezing point (or melting point) of water, though it isn't as substantial as the effect of pressure on boiling point. We could say that these values are at standard pressure, but realistically there is no noticeable difference of water's freezing point on various altitudes on earth.

It should be noted that if there are ions dissolved in the water, the freezing point will be lowered significantly due to the added solute.

Heat of Fusion

*Note that water does not actually freeze when it reaches 0° C, because it requires the removal of the "heat of fusion" (enthalpy) to change phase. Water will cool slightly below 0° and remain at that temperature until it has fully crystallized into ice.


Note: Ice crystals begin to form at 39°F, making water begin to slush. It will freeze solid at 32° F if heat continues to be lost (enthalpy of fusion).
0 degrees centigrade


2nd answer:

At standard pressure, water freezes at 32 degrees Fahrenheit, or 0 degrees Celsius. Oddly, solid water (ice) thaws or melts at 32 degrees, also.