Köppen’s Climate Classification

Köppen’s Climate Classification A Climates Af - Tropical Rain Forest (Tropical Wet) - Wet all seasons Controlling Factors: High year-round insolation and precipitation of doldrums (ITC); rising air along trade wind coasts Characteristics: Constant high temperatures Equal day and night length Low annual temperature range (3°F - 5°F) Even distribution of precipitation High cloud cover and humidity Vegetation: Rain forest vegetation. (selva) Jungle where light penetrates Am - Tropical Monsoon - Excessively wet during high sun season Controlling Factors: Summer onshore, winter offshore air movement related to shifting of ITC and changing pressure over large land masses. Transition between Af and Aw Characteristics: Heavy high-sun rainfall (esp. w/ orographic lifting) Short low-sun drought Small temperature range (3°F - 10°F) High temperature just prior to rainy season Vegetation: Forest vegetation with fewer species than tropical rainforest grading to jungle and thorn forest in drier margins Aw - Tropical Savanna - (Tropical Wet & Dry) Wet during high sun season, dry during low sun Controlling Factors: Alternation between high sun doldrums (ITC) and low-sun subtropical highs and trades caused by shifting winds and pressure belts. Characteristics: Distinct high-sun wet and low-sun dry seasons Highest temperature ranges for A climates Vegetation: Grasslands with scattered drought-resistant trees, scrub, thorn bushes B Climates BW - Desert (Arid) Controlling Factors: Descending, diverging circulation of subtropical highs; Continentality often linked with rainshadow location Characteristics: Aridity, low RH, irregular and unreliable rainfall Highest diurnal temperature range and highest percentage of sunshine Highest daytime temperatures and windy conditions Vegetation: Xerophytic veg., often barren, rocky or sandy surfaces BS – Steppe (Semi-Arid) Controlling Factors: Same as deserts, usually a transition zone between deserts (BW) and humid climates Characterisitics: Semiarid conditions Annual rainfall distribution similar to nearest humid climate Temperatures vary with latitude, elevation and continentality Vegetation: Dry savanna (tropics) or short grass vegetation C Climates Cs - Mediterranean - Hot dry summer Controlling Factors: West coast location between 30° and 40° N and S. Alternation between subtropical high in summer and westerlies in winter Characteristics: Mild, moist winters; hot, dry summers High percentage of sunshine High summer diurnal temperature range, frost danger Vegetation: Low, tough brush (chaparral); scrub woodlands olives, grapes, veges, citrus, irrigation Cfa, Cwa - Humid Subtropical - hot summers, year round precipitation Controlling Factors: East coast location (20° - 40° N and S) Humid onshore in summer; cyclonic storms in winter Characteristics: High humidity Summers like humid tropics Frost with polar air masses in winter Precipitation decreasing inland Vegetation: Mixed forest, grasslands, pines Cfb, Cfc - Marine West Coast - Mild summers, year-round precipitation Controlling Factors: West coast location. Under the year-round influence of the westerlies Characteristics: Mild winters, mild summers, low annual temperature range Heavy cloud cover, high humidity Frequent cyclonic storms, prolonged rain, drizzle, fog 3-4 month frost period Vegetation: Naturally forested, green year round D Climates Dfa, Dwa - Humid Continental - Hot Summer Controlling Factors: Location in lower middle latitudes (35° to 45°) Cyclonic storms along the polar front, westerlies, continentality Characteristics: Hot, often humid summers, occasional cold waves Rather large temperature range Vegetation: Broad-leaf deciduous and mixed forest Dfb, Dwb - Humid Continental - Mild Summer Controlling Factors: Location in the middle latitudes (45° to 55°) Cyclonic storms along the polar front, westerlies, continentality Characteristics: Moderate summers; long winters with clear, cold weather Large annual temperature ranges less precipitation Vegetation: Mixed or coniferous forest Dfc, Dwc, Dfd, Dwd - Subarctic Controlling Factors: Location in the higher middle latitudes (50° - 70°) Westerlies in summer, strong polar anticyclone in winter Occasional cyclone storms, extreme continentality Characteristics: Brief, cool summers; long, bitter winters Largest annual temperature ranges (lowest T outside Antarctica) Low precipitation Permafrost common Vegetation: Northern coniferous forest (taiga) Strongly acidic soils, poor drainage and swampy conditions E Climates ET - Tundra - Warmest month: 0°C to 10°C (32°F to 50°F) Controlling Factors: Location in the high latitudes; subsidence and divergence of the polar anticyclone Characteristics: Summerless; at least 9 months below freezing Low evaporation Coastal fog, strong winds Vegetation: Tundra veg. Permafrost; swamps or bog conditions during brief cool summers EF - Ice-Cap - Warmest month: below 0°C (32°F) Controlling Factors: Location in the high latitudes; subsidence and divergence of the polar anticyclone Elevation influence Characteristics: Summerless; all months below freezing World’s coldest temperature Extremely low precipitation (snow) gale-force winds Vegetation: Ice and snow covered; no vegetation; no exposed soils