Table 2 Climate types and defining criteria for Köppen.

From: Uncertainty maps for model-based global climate classification systems

Class

Type

Criteria

A (Tropical)

 

T_min ≥ 18 °C

Af. Tropical rainforest

P_min ≥ 60 mm

Aw. Tropical savanna

P_min < 60 mm

B (Dry)

 

P_annual ≤ P_threshold

BS. Steppe

P_annual ≥ P_threshold/2

BW. Desert

P_annual < P_threshold/2

C (Mesothermal)

 

T_min ≥ −3 °C & T_min < 18 °C

Cs. Warm climate dry summer

P_wmax ≥ 3 × P_smin

Cw. Warm climate dry winter

P_smax ≥ 10 × P_wmin

Cf. Humid temperate

P_smax < 10 × P_wmin & P_wmax < 3 × P_smin

D (Microthermal)

 

T_min < −3 °C & T_max > 10 °C

Dw. Cold climate dry winter

P_smax ≥ 10 × P_wmin

Df. Cold climate moist winter

P_smax < 10 × P_wmin

E (Polar)

 

T_max < 10 °C

ET. Tundra

T_max ≥ 0 °C & T_max < 10 °C

EF. Permafrost

T_max < 0 °C

  1. T_min = temperature coldest month, T_max = temperature hottest month, P_min = precipitation driest month, P_annual = annual precipitation, P_smin = minimum summer precipitation, P_smax = maximum summer precipitation, P_wmin = minimum winter precipitation, P_wmax = maximum winter precipitation, P_threshold = varies according to the following rules (if 70% of P_annual occurs in winter then P_threshold = 2 × T_avg; if 70% of P_annual occurs in summer then P_threshold = 2 × T_avg + 28; otherwise P_threshold = 2 × T_avg + 14).
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