temperature

A physical quantity that, applied to air and as a first approximation, we can define as the degree of agitation of the molecules of the gases that compose it, such that the hotter the air is, the greater the mobility of its molecules and, consequently, the higher its temperature. With cold the opposite occurs; molecular agitation is lower. The above definition - based on the kinetic theory of gases - is only applicable to an ideal gas, and we can only consider air as such under certain assumptions, so, strictly speaking, it is more appropriate to define temperature as the physical quantity of two systems or bodies in contact with each other (the air and the thermometer, in the case at hand), whose equality of values guarantees thermal equilibrium between them. Air temperature is obtained directly from the reading of a thermometer exposed to that element inside a meteorological screen, which guarantees the validity of the data, since, by proceeding in this way, undesirable overheating that could distort the measurement is avoided. In the International System of Units, temperature is expressed in degrees Kelvin (K), although in Meteorology the centigrade scale is habitually used, whose unit is the degree Celsius (°C). In the US the Fahrenheit temperature scale (°F) remains in use among the population, having fallen out of use in the rest of the English-speaking countries.