fârˈənhītˌ, temperature scale in which the temperature difference between two reference temperatures, the melting and boiling points of water, is divided into 180 equal intervals called degrees. The freezing point is taken as 32 degrees Fahrenheit and the boiling point as 212 degrees Fahrenheit. The scale was established by the German-Dutch physicist Gabriel Daniel Fahrenheit in 1724. William John Macquorn Rankine used it as the basis of his absolute temperature scale, now called the Rankine temperature scale, in 1859. Although the Fahrenheit scale was formerly used widely in English-speaking countries, many of these countries began changing to the more convenient Celsius temperature scale in the late 1960s and early 1970s; a notable exception is the United States, where the Fahrenheit scale is still in common use together with other English units of measurement. Temperatures on the Fahrenheit scale can be converted to equivalent temperatures on the Celsius scale by first subtracting 32° from the Fahrenheit temperature, then multiplying the result by 5 / 9, according to the formula (F−32) 5 / 9=C.

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