Question

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

Answer 1

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