Geography

Koppen Climate Classification Guidelines

If POTET exceeds Precip then B

BW = POTET more than 2x Precip

(desert)

h = mean annual temp > 18 C (64.4 F)

k = mean annual temp < 18 C (64.4 F)

BS = POTET less than 2x Precip

(steppe)

h = mean annual temp > 18 C (64.4 F)

k = mean annual temp < 18 C (64.4 F)

BWh, BSh – subtropical dry

BWk, BSk – mid-latitude dry

If Precip exceeds POTET then A, C, D or E

If consistently warm temperature profile, with all months averaging above 18 C (64.4 F) then A

f = if each and every month Precip exceeds 6 cm (2.4 in)

m = if one or more months Precip less than 6 cm (2.4 in); and 6 or more months Precip of 12 cm (7.2 in). Long wet season.

w = if one or more months Precip less than 6 cm (2.4 in); and 5 or less months Precip of 12 cm (7.2 in). Short wet season.

Af – tropical wet

Am and Aw – tropical wet/dry

If warmest month above 10 C (50 F); and coldest month above 0 C (32 F) but below 18 C (64.4 F) then C

a = warmest month above 18 C (64.4 F) Hot summer.

f = each and every month Precip exceeds 3 cm (1.2 in). Year round precipiation.

w = winter drought, wettest summer month 10 times more Precip than driest winter month (if f met and w met consider this a w). Winter drought.

Cfa, Cwa – Humid Subtropical

f = each and every month Precip exceeds 3 cm (1.2 in). Year round precipiation.

b = warmest month below 22 C (71.6 F) and with 4 months above 10 C (50 F)

c = warmest month below 22 C (71.6 F) and with 1 to 3 months above 10 C (50 F)

Cfb, Cfc – Marine West Coast

s = Winter months account for 70% or more of annual Precip. Summer drought.

a = warmest month above 18 C (64.4 F) Hot summer.

b = warmest month below 22 C (71.6 F) and with 4 months above 10 C (50 F)

Csa, Csb – Dry Summer Subtropical

If warmest month above 10 C (50 F); and coldest month below 0 C (32 F) then D

a = warmest month above 22 C (71.6 F) Hot summer.

f = each and every month Precip exceeds 3 cm (1.2 in). Year round precipiation.

w = winter drought, summer wettest month 10 times more Precip than driest winter month (if f met and w met consider this a w). Winter drought.

Dfa, Dwa – Humid Continental

f = each and every month Precip exceeds 3 cm (1.2 in). Year round precipiation.

b = warmest month below 22 C (71.6 F) Mild summer.

w = winter drought, summer wettest month 10 times more Precip than driest winter month (if f met and w met consider this a w). Winter drought.

Dfb, Dwb – Humid Continental

f = each and every month Precip exceeds 3 cm (1.2 in). Year round precipiation.

w = winter drought, summer wettest month 10 times more Precip than driest winter month (if f met and w met consider this a w). Winter drought.

c = 1 to 4 months above 10 C (50 F) Cool summer.

d = coldest month below -38 C (-36.4 F) Very cold winter.

Dfc, Dwc, Dwd – Subarctic

If warmest month below 10 C (50 F) then E

ET = warmest month 0-10 C (32-50 F). Precip exceeds small POTET. Polar Tundra

EF = warmest month below 0 C (32 F). Precip exceeds very small POTET. Polar Ice Cap

EM = all months above -7 C (20 F). Warmest month above 0 C (32 F). Annual range in monthly temperatures below -17 C (30 F). Polar Marine