|
Letter Symbol |
Climatic Characteristics |
Criteria |
|||
| 1st | 2nd | 3rd | |||
| A | Humid tropical | All months have an average T of 18°C (64°F) or higher | |||
| f | Tropical wet (rain forest) | Wet all seasons; all months have at least 6 cm (2.4 in) of rainfall | |||
| m | Tropical monsoon | Short dry season (3 to 5 months); rainfall in driest month is less than 6 cm (2.4 in) | |||
| w | Tropical wet and dry (savanna) | Winter dry season; rainfall in driest month is less than 6 cm (2.4 in) | |||
| B | Dry | Potential evaporation and transpiration exceed precipitation | |||
| S | Semi-arid (steppe) | The BS/BW boundary is exactly one-half the dry/humid boundary. Covers 14% of earth's land | |||
| W | Arid (desert) | True desert. Covers 12% of earth's land surface | |||
| h | Hot and dry | Mean annual T ≥ 18°C (64°F) | |||
| k | Cool and dry | Mean annual T £ 18°C (64°F) (Climate of the Wasatch Front's valleys = BSk) | |||
| C | Moist with mild winters | -3°C (27°F) £ Coolest month's average T £ 18°C (64°F) | |||
| w | Dry winters | Average rainfall of driest month £ 1/10 average rainfall of wettest month | |||
| s | Dry summers | Average rainfall of driest summer month < 4 cm (1.6 in) and £ 1/3 times rainfall of wettest month | |||
| f | Wet all seasons | Criteria for neither w or s cannot be met | |||
| a | Summers long and hot | Hottest month's average T > 22°C (72°F). At least 4 month's have average T > 10°C (50°F) | |||
| b | Summers long and cool | Average T of all months < 22°C (72°F). At least 4 month's have average T > 10°C (50°F) | |||
| c | Summers short and cool | Average T of all months < 22°C (72°F). 1 to 3 month's have average T > 10°C (50°F) | |||
| D | Moist with cold winters | Average T of coldest month £ -3°C (27°F). Average T of warmest month > 10°C (50°F) | |||
| w | Dry winters | Same as Cw. (Average rainfall of driest month £ 1/10 average rainfall of wettest month) | |||
| s | Dry summers | Same as Cs | |||
| f | Wet all seasons | Same as Cf | |||
| a | Summers long and hot | Same as Cfa | |||
| b | Summers long and cool | Same as Cfb | |||
| c | Summers short and cool | Same as Cfc | |||
| d |
Summers short and cool. Winters severe. |
Average T of coldest month £ -38°C (-36°F) | |||
| E | Polar climate | Average T of warmest month < 10°C (50°F) | |||
| T | Tundra | 0°C (32°F) < Average T of warmest month < 10°C (50°F). | |||
| F | Ice cap | Average T of warmest month £ 0°C (32°F) | |||
| H | Highland | Large swings of T and humidity in short distance because of varying elevation. 1000' elev. ~ 200 mi. NS dist. ~ 3° lat. | |||