Celsius Celsius The Celsius scale, also known as the centigrade scale, is a temperature scale used by the International System of Units (SI). As an SI derived unit, it is used by all countries except the United States, the Bahamas, Belize, the Cayman Islands and Liberia. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference between two temperatures or an uncertainty. Before being renamed to honor Anders Celsius in 1948, the unit was
Réaumur scale was used commonly in some parts of Europe until at least the mid-19th century, and in parts of Russia until the early 20th. Its main modern uses are in some Italian and Swiss factories for measuring milk temperature during cheese production, and in the Netherlands for measuring temperature when cooking sugar syrup for desserts and sweets. Réaumur scale The Réaumur scale (; °Ré, °Re, °r), also known as the "octogesimal division", is a temperature scale for which the freezing and boiling points of water are defined as 0 and 80 degrees respectively. The scale is named for René Antoine Ferchault