Meteorological instrumentation rain gauge. In 1714, Gabriel Fahrenheit creates a reliable scale for measuring temperature with a mercury-type thermometer. In 1742, Anders Celsius, a Swedish astronomer, proposed the 'centigrade' temperature scale, the predecessor of the current Celsius scale. In 1783, the first hair hygrometer is demonstrated by Horace-Bénédict de Saussure. In 1806, Francis Beaufort introduced his system for classifying wind speeds. The April 1960 launch of the first successful weather satellite, TIROS-1, marked the beginning of the age where weather information became available globally. This was also used to measure the temperature of the surrounding air. A thermometer measures air temperature, or
Celsius formally adopted "degree Celsius" in 1948, formally keeping the recognized degree symbol, rather than adopting the gradian/centesimal degree symbol. For scientific use, "Celsius" is the term usually used, with "centigrade" remaining in common but decreasing use, especially in informal contexts in English-speaking countries. It was not until February 1985 that the weather forecasts issued by the BBC switched from "centigrade" to "Celsius". Some key temperatures relating the Celsius scale to other temperature scales are shown in the table below. The "degree Celsius" has been the only SI unit whose full unit name contains an uppercase letter since the SI base