What temperature scale sets water’s freezing point at 0 degrees?

The Celsius scale sets water’s freezing point at 0 degrees under standard conditions.

The scale was proposed by Swedish astronomer Anders Celsius in 1742. Celsius originally described a reversed arrangement, with boiling and freezing points assigned oppositely, but later users adopted the direction now familiar: freezing at 0 and boiling at 100 at standard atmospheric pressure.

The Celsius scale is part of the metric system and is widely used for weather forecasts, scientific communication, and everyday temperatures. Its unit is the degree Celsius, written °C. A temperature change of one Celsius degree has the same size as a one-kelvin change.

The freezing and boiling points depend on pressure and dissolved substances. Pure water freezes at 0 °C and boils at 100 °C at approximately one atmosphere, so high mountains can have a lower boiling point.