How can you use the calculation of the climate ratio (p/ep) to determine a climate type?

The climate can be determined by calculating the ratio of precipitation (P) with potential evaporation (PE). The more P/PE value, the more humid the climate will be. The range would be:

Arid climate: <0.4

Semi arid climate : 0.4 - 0.8

Sub humid climate : 0.8 - 1.2

Humid climate: > 1.2