Regions where oceanic or subtropical highland climates (Cfb, Cfc, Cwb, Cwc) are found.
Anoceanic climate, also known as amarine climate ormaritime climate, is thetemperate climate sub-type inKöppen classification represented asCfb, typical of west coasts in higher middle latitudes of continents, generally featuring cool to warm summers and cool to mild winters (for their latitude), with a relatively narrow annualtemperature range and few extremes of temperature. Oceanic climates can be found in both hemispheres generally between 40 and 60 degrees latitude, with subpolar versions extending to 70 degrees latitude in some coastal areas. Other varieties of climates usually classified together with these includesubtropical highland climates, represented asCwb orCfb, andsubpolar oceanic orcold subtropical highland climates, represented asCfc orCwc. Subtropical highland climates occur in some mountainous parts of thesubtropics ortropics, some of which havemonsoon influence, while their cold variants and subpolar oceanic climates occur nearpolar ortundra regions.
Locations with oceanic climates tend to feature frequent cloudy conditions with precipitation, low hanging clouds, and frequent fronts and storms. Thunderstorms are normally few, since strong daytime heating and hot and cold air masses meet infrequently in the regions, but are more common in subtropical highland climates where these air masses meet more frequently due to the influence of hotter weather in the subtropics or tropics, especially in monsoon-influenced climates. In most areas with an oceanic climate, precipitation comes in the form of rain for the majority of the year. Most oceanic climate zones, however, experience at least one snowfall per year. Snowfall is more frequent and commonplace in the subpolar oceanic climates due to the colder weather in those locations.
Overalltemperature characteristics of the oceanic climates feature cool temperatures and infrequent extremes of temperature. In theKöppen climate classification, oceanic climates have a mean temperature of 0 °C (32 °F) or higher (or −3 °C (27 °F) or higher) in the coldest month, compared tocontinental climates where the coldest month has a mean temperature of below 0 °C (32 °F) (or −3 °C (27 °F)) in the coldest month. Summers are warm but not hot, with the warmest month having a mean temperature below 22 °C (72 °F).
Oceanic climates are not necessarily found in coastal locations on the aforementioned parallels; however, in most cases oceanic climates parallel higher middle latitude oceans.[clarification needed] The polarjet stream, which moves in a west to east direction across the middle latitudes, advances low pressure systems, storms, and fronts. In coastal areas of the higher middle latitudes (45–60° latitude), the prevailing onshore flow creates the basic structure of most oceanic climates. Oceanic climates are a product and reflection of the cool ocean adjacent to them. In the autumn, winter, and early spring, when the polar jet stream is most active, the frequent passing of marine weather systems creates the frequent fog, cloudy skies, and light drizzle often associated with oceanic climates. They are typically found poleward ofMediterranean climates, except in Australia where they are poleward of both such climates andhumid subtropical climates due to the shape of the continent.[citation needed] Only in Europe do they penetrate far inland, where they eventually transition into warm-summerhumid continental climates; in other continents, they are blocked by a large mountain range or limited by nearby oceans.[2]
The North AtlanticGulf Stream, a tropical oceanic current that passes north of the Caribbean and up the East Coast of the United States toNorth Carolina, then heads east-northeast to theGrand Banks of Newfoundland, is thought to greatly modify the climate of northwest Europe.[3] As a result of theNorth Atlantic Current, west coast areas located in high latitudes like Ireland, the UK, and Norway have much milder winters (for their latitude) than would otherwise be the case. The lowland attributes of western Europe also help drive marine air masses into continental areas, enabling cities such asDresden,Prague, andVienna to have maritime climates in spite of being located well inland from the ocean.
While most of Southern Europe is climaticallyMediterranean, some parts of Southern Europe also have oceanic climates. However, these instances of the climate are highly variable, and often somewhat anomalous. The north coast ofSpain, the westernAzores off the coast ofPortugal are too wet in summer to be Mediterranean, and too mild in summer to behumid subtropical, though they often have winter means above 9 °C (48 °F), unusual for European oceanic climates.
Another anomalous case can be found in northwestern Turkey, includingnorthern Istanbul. These places are, in a strict air-mass sense, not oceanic: they are affected by southerlies directly from the Mediterranean, and polar intrusions from Siberia.[5] Yet their position near the Black Sea makes them too wet in summer to beMediterranean, too mild during winter to behumid continental, and not hot enough in summer to behumid subtropical; thereforeKöppen classifies them as oceanic. Despite their anomalous position, however, their temperatures, around 4–5 °C (39–41 °F) in winter and 20–22 °C (68–72 °F) in summer, are not wholly atypical for European oceanic climates.
Some Eastern European regions such as the north ofCroatia andSerbia and some parts of theCzech Republic, also have oceanic climates; these are generally near the boundary for beinghumid continental.
The line between oceanic andcontinental climates in Europe runs in a generally northwest to southeast direction. For example, western Germany is more impacted by milder Atlantic air masses than eastern Germany. Thus, winters across Europe become colder to the east, and (in some locations) summers become hotter. The line between oceanic Europe andMediterranean Europe normally runs west to east and is related to changes in precipitation patterns and differences to seasonal temperatures; although intrusions of polar air, remnants of marine air-masses, and higher summer precipitation can create oceanic climates in Eastern Europe and transcontinental regions as far south as 40°N.[citation needed]
The oceanic climate exists in an arc spreading across the northwestern coast of North America from theAlaskan panhandle to northernWashington. In addition, some east coast areas such asBlock Island,Cape Cod,Martha's Vineyard, andNantucket have a similar climate.[6] And in the highlands of Central and South America with the variant Cfb. An extensive area of oceanic climates distinguishes the coastal regions of southernChile and extends into borderingArgentina.
The only noteworthy area of maritime climate at or near sea-level within Africa is in South Africa fromMossel Bay on theWestern Cape coast toPlettenberg Bay (theGarden Route), with additional pockets of this climate inland of theEastern Cape andKwaZulu-Natal coast. It is usually warm most of the year with no pronounced rainy season, but slightly more rain in autumn and spring. TheTristan da Cunha archipelago in the South Atlantic also has an oceanic climate.
Although oceanic climate is rare in Asia, subtropical highland climates and cold subtropical highland climates can be found in parts ofSouthwestern China, and theHimalayan regions of the northernIndian subcontinent.
The oceanic climate is prevalent in the more southerly parts ofOceania. A mild maritime climate is in existence in New Zealand. In Australia, the climate is found inTasmania, southern half ofVictoria and southeasternNew South Wales (southwards fromWollongong).
Some parts of the northeastern coast ofHonshu, such asMutsu, Aomori in Japan, feature this climate, which is rare in Asia due to the lack of a west coast in the middle latitudes.[8]
Temperate oceanic climates, also known as "marine mild winter" climates[9] or simply oceanic climates, are found either atmiddle latitudes. They are often found on or near the west coast of continents; hence another name for Cfb, "marine west coast climates". In addition to moderate temperatures year-round, one of the characteristics is the absence of a dry season. Except forEurope, this type of climate is confined to narrow bands of territory, largely in mid or high latitudes, although it can appear in elevated areas of continental terrain in low latitudes, e.g.plateaus in thesubtropics.[10] It exists in both hemispheres between 35° and 60°: at low altitudes betweenMediterranean,humid continental, andsubarctic climates.[11]
Westernsea breezes ease temperatures and moderates the winter, especially if warmsea currents are present, and cause cloudy weather to predominate. Precipitation is constant, especially in colder months, when temperatures are warmer than elsewhere at comparable latitudes. This climate can occur farther inland if no mountain ranges are present or nearby.[12] As this climate causes sufficient moisture year-round without permitting deep snow cover,vegetation typically prospers in this climate. Deciduous trees are predominant in this climate region. However, conifers such asspruce,pine, andcedar are also common in few areas, and fruits such asapples,pears, andgrapes can often be cultivated here.
In the hottest month, the average temperature is below 22 °C (72 °F), and at least four months feature average temperatures higher than 10 °C (50 °F). The average temperature of the coldest month must not be colder than −3–0 °C (27–32 °F), or the climate will be classified as continental.[10][13] The average temperature variations in the year are between 10–15 °C (50–59 °F), with average annual temperatures between 6–13 °C (43–55 °F).Rain values can vary from 50–500 cm (20–197 in), depending on whether mountains causeorographic precipitation.Frontal cyclones can be common in marine west coast regions, with some areas experiencing more than 150 rainy days annually, but strong storms are rare.[11]
Cfb climates are predominant in most of Europe except the northeast, as global temperatures became warmer towards late 20th and early 21st century. They are the main climate type inNew Zealand and theAustralian states ofTasmania,Victoria, and southeasternNew South Wales (starting from theIllawarra region). In North America, they are found mainly inVancouver Island and neighbouring parts ofBritish Columbia, as well as many coastal areas ofsoutheast Alaska. There are pockets of this iteration of Cfb climates in South American countries, mostly in regions of southern Chile and Argentina, parts of the provinces ofChubut,Santa Cruz, and southeastBuenos Aires province in Argentina. InWestern Asia, the climate can be found on theBlack Sea coast of northernTurkey andGeorgia, often transitional tohumid subtropical. While Cfb zones are rare in Africa, one dominates the coastline of theEastern Cape inSouth Africa.
The subtropical highland climate is a climate variety, often grouped together with oceanic climates, which exists in some mountainous or elevated portions of the world in either the subtropics or tropics. Despite the latitude, the higherelevations of these regions mean that the climate shares characteristics with oceanic climates.[18][19]
Subtropical highland climates with uniform rainfall (Cfb)[20] usually have rainfall spread relatively evenly throughout the year, similar to other oceanic climates, but unlike these climates, they have a highdiurnal temperature variation and low humidity, owing to their inland location and relatively high elevation. Subtropical highland climates withmonsoon influence (Cwb) have distinctivewet summers anddry winters.[21]
In locations outside the tropics, other than the drying trend in the winter, subtropical highland climates tend to be essentially identical to an oceanic climate, with mild summers and noticeably cooler winters, plus, in some instances, some snowfall. In the tropics, a subtropical highland climate typically features mild weather year-round. Temperatures there remain relatively constant throughout the year and snowfall is seldom seen due to warmer winters than most oceanic climates.
Areas with this climate feature monthly averages below 22 °C (72 °F) but above either 0 °C (32 °F) or −3 °C (27 °F) depending on isotherm used. At least one month's average temperature is below 18 °C (64 °F). Without their elevation, many of these regions would likely feature eitherhumid subtropical ortropical climates.
Areas with subpolar oceanic climates feature an oceanic climate but are usually located closer to polar regions, with long but relatively mild winters and short, cool summers. As a result of their location, these regions tend to be on the cool end of oceanic climates, approachingpolar regions. Snowfall tends to be more common here than in other oceanic climates. Subpolar oceanic climates are less prone to temperature extremes thansubarctic climates orcontinental climates, featuring milder winters than these climates. Subpolar oceanic climates feature only one to three months of average monthly temperatures of at least 10 °C (50 °F). As with oceanic climates, none of its average monthly temperatures fall below -3.0 °C (26.6 °F) or 0 °C depending on the isotherm used. Typically, these areas in the warmest month experience daytime maximum temperatures below 17 °C (63 °F), while the coldest month features highs slightly above freezing and lows near or just below freezing while keeping the average warm enough. It typically carries aCfc designation, though very small areas inArgentina andChile have summers sufficiently short to beCwc with fewer than four months over 10 °C (50 °F).[23]
This variant of an oceanic climate is found in parts of coastalIceland, theFaroe Islands, upland/mountainous parts ofScotland andNorthern England, northwestern coastal areas ofNorway (most ofLofoten,Vesterålen, warmest part ofTromsø reaching to 71°N on some islands),[24] uplands/highlands in western Norway, theAleutian Islands ofAlaska and northern parts of theAlaskan Panhandle, the southwest ofArgentina andChile, and a few highland areas ofTasmania, and theAustralian andSouthern Alps.[25] This type of climate is even found in very remote parts of theNew Guinea Highlands. The classification used for this regime is Cfc.[1] Temperatures above 30 °C (86 °F) and below −20 °C (−4 °F) are rare. In the most marine areas under this regime, temperatures above 20 °C (68 °F) are extreme weather events, even during summer.
Small areas in Yunnan,Sichuan; parts ofBolivia andPeru; and parts ofMount Kilimanjaro inTanzania have summers sufficiently short to beCwc with fewer than four months over 10 °C (50 °F).[23] This is the cold variant of the monsoon-influenced subtropical highland climate.El Alto,Bolivia is one of the few confirmed cities that features this variation of the subtropical highland climate.
^Tapper, Andrew; Tapper, Nigel (1996). Gray, Kathleen (ed.).The weather and climate of Australia and New Zealand (First ed.). Melbourne, Australia: Oxford University Press. p. 300.ISBN978-0-19-553393-4.
"Marine (Humid) West Coast Climate", June 21, 2007,The Physical Environment: an Introduction to Physical Geography, Michael Ritter, University of Wisconsin–Stevens Point
"EPIC Web Browser", NOAA, on-line ocean observational data collection
