Köppen climate classification
The Köppen climate classification divides climates into five main climate groups, with each group being divided based on seasonal precipitation and temperature patterns. The five main groups are "A" (tropical), "B" (dry), "C" (temperate), "D" (continental), and "E" (polar). Each group and subgroup is represented by a letter. All climates are assigned a main group (the first letter). All climates except for those in the "E" group are assigned a seasonal precipitation subgroup (the second letter). For example, "Af" indicates a tropical rainforest climate. The system assigns a temperature subgroup for all groups other than those in the "A" group, indicated by the third letter for climates in "B", "C", and "D", and the second letter for climates in "E". For example, "Cfb" indicates an oceanic climate with warm summers as indicated by the ending "b". Climates are classified based on specific criteria unique to each climate type.
Guanajuato
Climates in the state are grouped by precipitation and average temperatures into three major groups. The semi-arid climate is characterized by the fact that evaporation often exceeds precipitation. Most of the vegetation in these areas is arid grassland with desert plants such as nopal. These climates cover about forty percent of the state, mostly in the north. Semi-arid temperate regions are found in the municipalities of San Felipe, San Diego de la Unión, San Luis de la Paz, part of Dolores Hidalgo and San José de Iturbide, where precipitation varies between 400 and 500 mm and the average temperature is between 16 and 18 °C. Semi-arid semi hot climates can be found north of Dolores Hidalgo, around León and in areas near Celaya. In these municipalities, rainfall averages between 600 and 700 mm and the average annual temperature is between 18 and 20 °C. Temperate climates are judged by the presence of holm oak and pine forest, pine forests and/or pine forests with meadows. Humidity varies in these forest regions. Temperate semi-moist areas are mostly found in the southeast municipalities of Apaseo, Coroneo and Jerécuaro and in the center of the state. Precipitation varies from 600 to 700 mm and the average temperature is between 16 and 18 °C. Temperate and somewhat humid climates have rainfall averages of between 700 and 800 mm, with temperatures between 16 and 18 °C. These can be found in Pénjamo, Coroneo, Jerécuaro and parts of Guanajuato (municipality) and Dolores Hidalgo. Temperate climates with the most humidity are found in the Santa Rosa and municipality of Guanajuato. These have rainfall averages of over 800 mm and average temperatures of under 16 °C. Hot and moist climates in the state have temperatures ranging from 18 to 22 °C and are associated with tropical rainforest, with some grassland. These climates are subdivided into two types, one that receives less rainfall with a significant dry season and the other which is wetter. The drier type is found in Abasolo, Irapuato, Salamanca and Romita. In total, these hot and relatively moist climates can be found in about 40% of the state.