FLOW CHART FOR KÖPPEN’S CLIMATE CLASSIFICATION
FIRST LETTER SYMBOL A TROPICAL CLIMATES Monthly temperatures all greater than or equal to 18°C. B DRY CLIMATES Potential evapotranspiration exceeds precipitation. C WET TEMPERATE (MARITIME) CLIMATES Average temperature of coldest month is at least -3°C but less than 18°C; warmest month at least 10°C. D COOL TEMPERATE (CONTINENTAL) CLIMATES Coldest month less than -3°C; warmest month at least 10°C. E POLAR CLIMATES Monthly temperatures all less than 10°C. SECOND LETTER SYMBOL F FROST/ICE All months less than 0°C. S STEPPE See Figure 1. T TUNDRA Warmest month at least 0°C. W DESERT See Figure 1. f WET ALL YEAR See Figure 2; or, every month receives at least 30 mm of precipitation for C and D climates. m MONSOON Short dry season. s SUMMER DRY See Figure 2; or, driest summer month less than or equal to 1/3 of precipitation of wettest winter month. w WINTER DRY See Figure 2; or, driest winter month less than or equal to 1/10 of precipitation of wettest summer month. THIRD LETTER SYMBOL a HOT SUMMER Warmest month greater than or equal to 22°C. b WARM LONG SUMMER At least 4 months have temperatures of 10°C or above but under 22°C. c SHORT SUMMER 1 to 3 months have temperatures of 10°C or above but under 22°C. d SEVERE WINTER Coldest month less than -38°C. h HOT Annual temperature is 18°C or greater. k COOL Annual temperature is less than 18°C.
FLOW CHART FOR KÖPPEN’S CLIMATE CLASSIFICATION
T and P refer to normal monthly values of Temperature and Precipitation
START
Is every T<10°C?
YES
Is every T<0°C?
YES NO
EF
BWk
NO
Is it a “B” climate? Use Figure 1.
ET
YES NO
BWh
YES
Is it “BW” or “BS”? Use Figure 1.
BW BS
Is annual T<18°C?
BSk
YES NO
BSh
NO
Is every T!18°C?
Is annual T<18°C?
Am
YES
Is every P!60mm?
YES NO
Af
Am Aw
Aw
NO YES
Use Figure 2 to determine Am, Aw, or As. Is every P!30mm?
As
As
Is every T!-3°C?
YES
Is the hottest T!22°C?
YES NO
Cfa Cfb
YES
Are at least 4 T!10°C? Cfc
NO
NO
Cwb
NO
Is the driest winter P"1/10 of wettest summer P?
YES
Is the hottest T!22°C?
YES
Cwa
YES NO
Are at least 4 T!10°C? Cwc-None exist
NO YES
Is the hottest T!22°C?
NO
Csa
Csb
Is the driest summer P"1/3 of wettest summer P?
YES
YES
Are at least 4 T!10°C?
NO
NO
NO
Is every P!30mm
Csc-None exist
YES
Is the coldest T<-38°C?
YES NO
Dfd
NO
Is the driest winter P"1/10 of wettest summer P?
YES
Is the hottest T!22°C?
Dfa Dfb
YES
Is the coldest T<-38°C?
YES NO
Are at least 4 T"10°C?
YES
Dwd
NO
Dfc
NO
Is the driest summer P"1/3 of wettest summer P?
YES
Ds-None exist
NO
Is the hottest T!22°C?
YES NO
Dwa
Dwb
YES
Are at least 4 T!10°C?
NO
NO
Dwc
FLOW CHART FOR KÖPPEN’S CLIMATE CLASSIFICATION
FIGURE 1 30°C Normal Annual Temperature Figure 1: First, divide the year into two six-month seasons: AprilSeptember and October-March, representing Summer or Winter in their respective hemispheres. If 70% or more of the annual precipitation total falls into one of these two seasons, then that season is considered to have a precipitation concentration. If not, then precipitation is considered to fall evenly throughout the year. 25°C 20°C 15°C 10°C 5°C 0°C -5°C -10°C 0 mm 100 mm 200 mm 300 mm 400 mm 500 mm 600 mm 700 mm 800 mm 800 mm Af Aw, As 70 mm 900 mm 80 mm 900 mm -15°C A, C, D, or E BW BS Even Distribution
Normal Annual Precipitation Summer 30°C Normal Annual Temperature 25°C 20°C 15°C 10°C 5°C 0°C -5°C -10°C 0 mm 100 mm 200 mm 300 mm 400 mm 500 mm 600 mm 700 mm 800 mm 900 mm -15°C A, C, D, or E BW BS Normal Annual Temperature Concentration 30°C 25°C 20°C 15°C 10°C 5°C 0°C -5°C -10°C 0 mm 100 mm 200 mm 300 mm 400 mm 500 mm 600 mm 50 mm 700 mm 60 mm -15°C A, C, D, or E BW BS Winter Concentration
Normal Annual Precipitation FIGURE Figure 2: First, divide the year into two six-month seasons: AprilSeptember and October-March, representing Summer or Winter in their respective hemispheres. If 70% or more of the annual precipitation total falls into one of these two seasons, then that season is considered to have a precipitation concentration. If not, then precipitation is considered to fall evenly throughout the year. Mean Annual Precipitation 2
Normal Annual Precipitation
3,000 mm 2,500 mm 2,000 mm 1,500 mm 1,000 mm 500 mm 0 mm 10 mm 20 mm 30 mm 40 mm 0 mm Am