fahrenheitasteikko

Fahrenheitasteikko, commonly referred to as the Fahrenheit scale, is a temperature scale primarily used in the United States and a few other regions. It was devised by the physicist Daniel Gabriel Fahrenheit and introduced in 1724. The scale defines the freezing point of water as 32 °F and the boiling point as 212 °F at standard atmospheric pressure, with 180 equal divisions between these two fixed points.

Historically, Fahrenheit based the scale on three fixed reference points. He set 0 °F as the temperature of a brine solution of ice and salt, 32 °F as the freezing point of water, and 212 °F as the boiling point of water. The unit used is the degree Fahrenheit, symbolized as °F.

Usage of Fahrenheit is mainly limited to the United States and its territories, with some dependent regions and Caribbean and Pacific territories also employing it in everyday life. In scientific and most international contexts, Celsius is the preferred scale, while Fahrenheit remains standard for weather reports, household temperatures, and some consumer products in the U.S.

Conversion between scales follows simple formulas: F = C × 9/5 + 32 and C = (F − 32) × 5/9. Notable equivalences include −40 °C = −40 °F. For reference, 0 °C corresponds to 32 °F and 100 °C corresponds to 212 °F at sea level.