The degree Celsius (symbol: °C) is an SI derived unit of temperature. The freezing point of water is designated at 0 °C and the boiling point at 100 °C. The International System of Units (abbreviated SI from the French language name Système International dUnités) is the most widely used system of units. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ...

Definition

A change in temperature of 1 °C is equal to a change in temperature of 1 K. The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ...

Absolute zero is -273.15 °C In physics, absolute zero is a fundamental lower bound on the temperature of a macroscopic system. ...

For temperature readings,

t_°C = t_K - 273.15

Origin

It is named after the Swedish astronomer Anders Celsius (1701 to 1744), who first proposed a similar system in 1742. Anders Celsius The observatory of Anders Celsius, from a contemporary engraving. ...

Conversions

It has been suggested that SI derived unit#Conversion between kelvins and degrees Celsius be merged into this article or section. (Discuss)

Temperature conversion: Image File history File links Please see the file description page for further information. ... SI derived units are part of the SI system of measurement units and are derived from the seven SI base units. ...

• °F = °C × 1.8 + 32
• °C = (°F – 32) / 1.8
• K = °C + 273.15
• °C = K – 273.15

Explanation

The temperature scale invented by Anders Celsius was originally designed so that the freezing point of water is 100 degrees, and its boiling point is 0 degrees at standard atmospheric pressure. This was reversed to its modern order some time after his death, in part at the instigation of Daniel Ekström, the manufacturer of most of the thermometers used by Celsius. Several other people, including Elvius from Sweden (1710) and Christian of Lyons (1743), independently invented the same temperature scale. The oft-quoted claim that the botanist Carolus Linnaeus (1740) is amongst those is unsubstantiated. The Delisle scale was another temperature scale that ran "downward". Water (from the Old English word wæter; c. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ... A thermometer is a device used to measure temperatures or temperature changes. ... Carolus Linnaeus Carl Linnaeus, also known after his ennoblement as Carl von Linné â–¶(?), and in English usually under the Latinized name Carolus Linnaeus (May 23, 1707 – January 10, 1778), was a Swedish botanist who laid the foundations for the modern scheme of taxonomy. ... The Delisle scale is a temperature scale invented in 1732 by the French astronomer Joseph-Nicolas Delisle (1688–1768). ...

In 1948 there were three names for the same unit:

• centigrade
• centesimal degree
• degree Celsius

From that date, the official name was chosen to be degree Celsius.

Since there are 100 graduations between these two reference points, the original term for this system was centigrade (100 parts) or centesimal. In 1948 the system's name was officially changed to Celsius (a third name which had also been in use before then) by the 9th General Conference on Weights and Measures (CR 64), both in recognition of Celsius himself and to eliminate confusion caused by conflict with the use of the SI centi- prefix. While the values for freezing and boiling of water remain approximately correct, the original definition is unsuitable as a formal standard: it depends on the definition of standard atmospheric pressure which in turn depends on the definition of temperature. The current official definition of the Celsius sets 0.01 ℃ to be at the triple point of water and a degree to be 1/273.16 of the difference in temperature between the triple point of water and absolute zero. This definition was adopted in 1954 at the 10th General Conference on Weights and Measures. The definition given for the kelvin is similar, the difference being that 0 K is absolute zero. The Conférence générale des poids et mesures (General Conference on Weights and Measures or CGPM) is one of the three organizations established to maintain the SI system under the terms of the Metre Convention (1875). ... The International System of Units (abbreviated SI from the French language name Système International dUnités) is the most widely used system of units. ... In physics, the triple point of a substance is the temperature and pressure at which three phases (gas, liquid, and solid) of that substance may coexist in thermodynamic equilibrium. ... In physics, absolute zero is a fundamental lower bound on the temperature of a macroscopic system. ... 1954 (MCMLIV) was a common year starting on Friday of the Gregorian calendar. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ...

The degree Celsius is the only SI unit whose full unit name ("degree Celsius", not "Celsius") in English includes an upper case letter. That is a quirk of English, because it is a proper adjective rather than a noun (before the name was changed from "degree Kelvin" to "kelvin" in 1967, that was another SI unit containing a capital letter in English). SI prefixes are applied normally, so you can have, for example, a measurement of « 12 m℃ ». The English language is a West Germanic language that originates in England. ... An SI prefix is a prefix that can be applied to an SI unit to form a decimal multiple or submultiple. ...

The Celsius scale is used throughout most of the world for day-to-day purposes. In broadcast media it was still frequently referred to as centigrade until the late 1980s or early 1990s, particularly by weather forecasters on European networks such as the BBC, ITV, and RTÉ. In the United States and Jamaica, Fahrenheit remains the dominant scale for everyday temperature measurement, although degree Celsius and kelvin are used for aeronautical and scientific applications. Corporate logo of the British Broadcasting Corporation The British Broadcasting Corporation (BBC) is the national broadcaster of the United Kingdom. ... Independent Television (ITV) is the name given to the original network of British commercial television broadcasters, set up to provide competition to the BBC. In England and Wales the channel was recently rebranded ITV1 by ITV plc who own the regional broadcasting licences for the regions. ... Radio Telefís Éireann (RTÉ; Irish for Radio and Television of Ireland) is the national publicly-funded broadcaster of Ireland. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ...

In the United Kingdom, Celsius is the official scale used by the government and the media. It is also the only scale used in British cooking and temperature controllers (for example, room thermostats). Some of the British media, provide Fahrenheit equivalents for temperatures well above room temperature. Temperatures below room temperature are almost exclusively quoted in degrees Celsius in the UK.