Humid climes (A, B, C2)

Arid index (I_a)

r → without or with a small hydric deficit

0 ≤ I_a < 16.7

s → moderate hydric deficit in the summer

16.7 ≤ I_a < 33.3

w → moderate hydric deficit in the winter

16.7 ≤ I_a < 33.3

s₂ → big hydric deficit in the summer

I_a ≥ 33.3

w₂ → big hydric deficit in the winter

I_a ≥ 33.3

Dry climes (C1, D, E)

Arid index (I_a)

d → small or null water surplus

0 ≤ I_h < 10

s → moderate water surplus in the summer

10 ≤ I_h < 20

w → moderate water surplus in the winter

10 ≤ I_h < 20

s₂ → big water surplus in the summer

I_h ≥ 33.3

w₂ → big water surplus in the winter

I_h ≥ 33.3