page_title: Earth rainfall climatology
section_title: Role in Köppen climate classification
hierarchical_section_title: Earth rainfall climatology / Role in Köppen climate classification
context_page_description: Earth rainfall climatology Is the study of rainfall, a sub-field of meteorology. Formally, a wider study includes water falling as ice crystals, i.e. hail, sleet, snow. The aim of rainfall climatology is to measure, understand and predict rain distribution across different regions of planet Earth, a factor of air pressure, humidity, topography, cloud type and raindrop size, via direct measurement and remote sensing data acquisition. Current technologies accurately predict rainfall 3–4 days in advance using numerical weather prediction. Geostationary orbiting satellites gather IR and visual wavelength data to measure realtime localised rainfall by estimating cloud albedo, water content, and the corresponding probability of rain.
  Geographic distribution of rain is largely governed by climate type, topography and habitat humidity. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation. On the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating.
context_section_description: The Köppen classification depends on average monthly values of temperature and precipitation.  The most commonly used form of the Köppen classification has five primary types labeled A through E. Specifically, the primary types are A, tropical; B, dry; C, mild mid-latitude; D, cold mid-latitude; and E, polar. The five primary classifications can be further divided into secondary classifications such as rain forest, monsoon, tropical savanna, humid subtropical, humid continental, oceanic climate, Mediterranean climate, steppe, subarctic climate, tundra, polar ice cap, and desert.
  Rain forests are characterized by high rainfall, with definitions setting minimum normal annual rainfall between 1,750 millimetres (69 in) and 2,000 millimetres (79 in).  A tropical savanna is a grassland biome located in semi-arid to semi-humid climate regions of subtropical and tropical latitudes, with rainfall between 750 millimetres (30 in) and 1,270 millimetres (50 in) a year.  They are widespread on Africa, and are also found in India, the northern parts of South America, Malaysia, and Australia.  The humid subtropical climate zone where winter rainfall (and sometimes snowfall) is associated with large storms that the westerlies steer from west to east. Most summer rainfall occurs during thunderstorms and from occasional tropical cyclones.  Humid subtropical climates lie on the east side continents, roughly between latitudes 20° and 40° degrees away from the equator.
  An oceanic (or maritime) climate is typically found along the west coasts at the middle latitudes of all the world's continents, bordering cool oceans, as well as southeastern Australia, and is accompanied by plentiful precipitation year-round.  The Mediterranean climate regime resembles the climate of the lands in the Mediterranean Basin, parts of western North America, parts of Western and South Australia, in southwestern South Africa and in parts of central Chile. The climate is characterized by hot, dry summers and cool, wet winters.  A steppe is a dry grassland.  Subarctic climates are cold with continuous permafrost and little precipitation.
  The tropical zones have the highest number of storm events followed by the temperate climate. In a recent study, researchers from 63 countries combined 30-minutes rainfall data in order to estimate the global rainfall erosivity (an index combining the amount, frequency and intensity of rainfall). The arid and cold climate zones have very low number of erosive events.
caption: Updated Köppen-Geiger climate map[4]                       Af   Am   Aw     BWh   BWk   BSh   BSk     Csa   Csb     Cwa   Cwb     Cfa   Cfb   Cfc     Dsa   Dsb   Dsc   Dsd     Dwa   Dwb   Dwc   Dwd     Dfa   Dfb   Dfc   Dfd     ET   EF