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.
Trewartha climate classification
Climates with no more than two dry months (defined as having less than , average precipitation, same as per Köppen) are classified "Ar", while others are classified "Aw" if the dry season is at the time of low sun/short days or "As" if the dry season is at the time of high sun/long days. There was no specific monsoon climate identifier in the original scheme, but "Am" was added later, with the same parameters as Köppen's (except that at least three months, rather than one, must have less than 60 mm average precipitation).