Countries that use Fahrenheit (°F).      Countries that use both Fahrenheit (°F) and Celsius (°C).      Countries that use Celsius (°C).

Celsius (more precisely, a degree Celsius), sometimes called centigrade, is a unit of measurement used in many countries to measure temperature. This unit was created by Anders Celsius (1701–1744), a Swedish astronomer.

0 degrees (°) Celsius is the melting point of pure water at sea level (normal pressure). 100° Celsius is the boiling point of water at normal pressure. (Water boils at a lower temperature at higher altitudes).

1 °C is therefore one hundredth (the 100th part) of that difference.