What is the SI unit for temperature?

The SI unit for temperature is the Kelvin. This unit is part of the International System of Units (SI) and is widely used in scientific contexts. The Kelvin scale is absolute, meaning it starts from absolute zero, which is the theoretical point where all molecular motion ceases. In this scale, one Kelvin unit is equivalent to one degree Celsius, but it does not have negative values, which is particularly important in scientific measurements and calculations. This allows for more straightforward computations in thermodynamics and other scientific fields where temperature is a critical variable.

Celsius, although commonly used, is not an SI unit; it is a derived scale based on the freezing and boiling points of water. Fahrenheit and Rankine are also non-SI units, predominantly used in specific regions or for particular applications, but they do not hold the same universal acceptance as the Kelvin in scientific literature.