What Is Celsius (°C)?
Definition
Celsius (°C): The everyday temperature scale in most of the world, symbol °C. The SI defines it from the kelvin: a Celsius temperature is the kelvin temperature minus 273.15. A difference of one degree Celsius equals one kelvin.
Celsius (°C) is the temperature scale used for weather, body temperature and cooking in most of the world. On it, water at normal air pressure freezes at about 0 °C and boils at about 100 °C. The SI defines the Celsius scale from the kelvin, and a change of 1 °C equals a change of 1 K.
Where it appears in the formulas
t(°C) = T(K) − 273.15 and t(°F) = 1.8 × t(°C) + 32. The temperature converter takes these definitions from the BIPM SI Brochure and NIST SP 811. For example, 37 °C is 98.6 °F and 310.15 K.
Celsius or centigrade
The official name is the degree Celsius, after the Swedish astronomer Anders Celsius. Centigrade is an older name for the same scale.