The 30 Köppen climate zones
Five major groups, each split by rainfall pattern and temperature. Share of land is for 1991 to 2020, outside Antarctica.
A: Tropical (22% of land)
Warm all year round. There is no cold season, only wetter and drier ones. Not arid, and even the coldest month averages 18 °C or more.
- Af Tropical rainforest Hot, wet and green every month of the year. (5.1% of land)
- Am Tropical monsoon Hot all year, with a very wet season and a short dry spell. (3.6% of land)
- Aw Tropical savannah Hot all year, with a clear dry season. (13% of land)
B: Arid (32% of land)
Dry climates, where evaporation could use up more water than the rain supplies. Hot or cold, they are defined by dryness first. Dry: yearly rainfall is below ten times a threshold that rises with temperature and depends on the season in which the rain falls.
- BWh Hot desert Very dry and hot. (16% of land)
- BWk Cold desert Very dry, with cool or cold conditions through the year. (3.9% of land)
- BSh Hot semi-arid (steppe) Dry and hot, but with enough rain for grass. (6.4% of land)
- BSk Cold semi-arid (steppe) Dry grassland with cool or cold conditions. (5.5% of land)
C: Temperate (13% of land)
Mild winters and a real summer. Where people have settled in large numbers, this is often the group they have settled in. Not arid, the warmest month is above 10 °C, and the coldest month is between 0 °C and 18 °C.
- Csa Hot-summer Mediterranean Dry, hot summers and mild, wetter winters. (1.2% of land)
- Csb Warm-summer Mediterranean Dry, warm summers and mild, wetter winters. (0.8% of land)
- Csc Cold-summer Mediterranean Dry summers, short and cool. (0% of land)
- Cwa Humid subtropical with dry winter Hot, wet summers and dry, mild winters. (3% of land)
- Cwb Subtropical highland (dry winter) Mild all year, with a dry winter. (1.2% of land)
- Cwc Cold subtropical highland (dry winter) Short, cool summers and dry winters at altitude. (less than 0.1% of land)
- Cfa Humid subtropical Hot, humid summers and mild winters, with rain all year. (4.7% of land)
- Cfb Temperate oceanic Mild and damp, with no extremes. (2.3% of land)
- Cfc Subpolar oceanic Cool, damp and breezy, with very short summers. (less than 0.1% of land)
D: Cold (continental) (27% of land)
A proper winter with the coldest month at or below freezing, followed by a summer warm enough for trees. Found in the middle and high latitudes of the northern hemisphere, far from the moderating sea. Not arid, the warmest month is above 10 °C, and the coldest month is at or below 0 °C.
- Dsa Hot-summer continental with dry summer Cold winters and hot, dry summers. (0.3% of land)
- Dsb Warm-summer continental with dry summer Cold winters and warm, dry summers. (0.6% of land)
- Dsc Subarctic with dry summer Cold, short summers, dry in the warm months. (1.2% of land)
- Dsd Subarctic with dry summer and very cold winter Extremely cold winters and a dry, short summer. (less than 0.1% of land)
- Dwa Hot-summer continental with dry winter Hot, wet summers and cold, dry winters. (0.8% of land)
- Dwb Warm-summer continental with dry winter Warm summers and cold, dry winters. (1.3% of land)
- Dwc Subarctic with dry winter Short, cool summers and long, cold, dry winters. (2% of land)
- Dwd Subarctic with dry winter and very cold winter Some of the coldest winters outside the poles. (0.2% of land)
- Dfa Hot-summer humid continental Hot summers and cold winters, with rain all year. (1.8% of land)
- Dfb Warm-summer humid continental Warm summers and cold, snowy winters, with rain all year. (7.5% of land)
- Dfc Subarctic (boreal) Long, cold winters and short, cool summers. (11% of land)
- Dfd Subarctic with very cold winter Among the coldest winters on Earth outside the poles. (less than 0.1% of land)
E: Polar (6.3% of land)
No real summer. Defined by cold rather than by rain. Not arid, and even the warmest month is no warmer than 10 °C.
- ET Tundra Too cold for trees; a brief, chilly summer. (5% of land)
- EF Ice cap (frost) Frozen all year. (1.3% of land)