climate

The set of average atmospheric conditions of a given place over a period of time of at least 30 years, according to the recommendations of the World Meteorological Organization. It is characterized by different statistical values, such as the mean, the variance, or the probability of occurrence of extreme values, of the meteorological elements of the place in question. It has its etymological origin in the Greek word κλίμα (klíma), which means slope or inclination. Ancient Greek geographers and astronomers used this name for each of the terrestrial bands delimited by parallels, since they considered that climate was dictated by the inclination of a given region's horizon line with respect to the Earth's axis of rotation. That concept evolved into the current one, where meteorological variability is taken into account. For geographical science, climate is what is perceived and experienced by human beings in a given territory over a sufficiently long series of years. It should be noted that climate is different from weather, although it is very common to consider them synonyms. While weather is what is immediate, what is happening in the atmosphere at a given moment, climate must be seen as a film showing the succession of atmospheric states that have occurred in a place during the aforementioned 30 years. In that feature film, weather would be each of the frames. Nowadays, there is a growing tendency to extend the concept of climate beyond the strictly atmospheric sphere, becoming a statistical description of the state of the climate system as a whole.