Humid continental climate
The humid continental climate is a climate found over large areas of landmasses in the temperate regions of the mid-latitudes where there is a zone of conflict between polar and tropical air masses. The humid continental climate is marked by variable weather patterns and a large seasonal temperature variance. Summers are often warm and humid with frequent thunderstorms and winters can be very cold with frequent snowfall and persistent snow cover. The seasonal temperature variance is typically 25-35°C (45-63°F) and increases as one moves further inland and away from the moderating influence of the ocean. Places with at least four months of average daily temperatures above 10 °C (50 °F) and at least one month below −3 or 0 °C (27 or 32 °F) depending on source, and which do not meet the criteria for an arid or semiarid climate, are classified as humid continental.[1] It is most prominent over a wide section of central and eastern North America, parts of Eastern Europe, northwestern Asia and areas adjacent to the Yellow Sea, the Korean Peninsula and Northern Japan. It is only found in small pockets (micro climates) in the Southern Hemisphere, including higher elevations of South Island.
Dfa/Dwa: Hot (or very warm) summer subtype
A hot (or very warm) version of a continental climate features an average temperature of at least 22 °C (72 °F) in its warmest month. The warmest month is usually in July, though it some cases it can be in August. Average July afternoon temperatures in this zone generally average between 26 and 32 °C (79 and 90 °F) while the average temperature of the coldest month is −3 °C (27 °F) or colder. In some instances, the average temperature of the coldest month can be far below −3 °C (27 °F). Within North America it includes much of the eastern and midwestern portions of the United States and part of southern Ontario, Canada from the Atlantic to the 100th meridian and generally in the range of 39°N to 44°N latitude (with a larger north-south spread in the western portion due to the lack of maritime influences, while covering a very small area in the eastern regions before bordering on humid subtropical); precipitation increases the further eastward in this zone and is less seasonally uniform in the west; this area includes the following regions:
- Portions of southern New York
- Most of Pennsylvania (except SE middle Atlantic plain)
- Northwestern New Jersey
- Extreme western Virginia (in higher elevations)
- Most of West Virginia (except in valley areas at lower elevations)
- Most of Ohio
- Most of Indiana
- Most of Illinois
- Most of Missouri
- Iowa
- Eastern Nebraska
- Eastern Kansas
- Southeastern South Dakota
- Extreme Southern Minnesota
- Southern Wisconsin (south of Madison)
- Southern Michigan (south of Saginaw)
- Southern Ontario (southwest of Toronto)
- Most of Connecticut
- Most of Rhode Island
- Most of Massachusetts
- Extreme southern Vermont
- Extreme southern New Hampshire
- Extreme southwestern Maine
Some of the major North American cities in this zone:
- Chicago, Illinois
- Cleveland, Ohio
- Columbus, Ohio
- Des Moines, Iowa
- Detroit, Michigan
- Grand Rapids, Michigan
- Hartford, Connecticut
- Indianapolis, Indiana
- Kansas City, Missouri
- Milwaukee, Wisconsin
- Minneapolis, Minnesota
- Saint Paul, Minnesota
- Omaha, Nebraska
- Sioux Falls, South Dakota
- Toledo, Ohio
- Toronto, Ontario
- Windsor, Ontario
The 0 °C (32 °F) isotherm (freeze line) or the −3 °C (27 °F) isotherms (persistent snow line) are the possible lines dividing the humid continental and the humid subtropical climates. The Koppen climate classification, the most popular climate classification, uses −3 °C (27 °F). In between these lines are the following places:
- Boston, Massachusetts
- Cincinnati, Ohio
- Pittsburgh, Pennsylvania
- Providence, Rhode Island
- St. Louis, Missouri
Some regions in this zone:
- The far south of New York (excluding New York City)
- Coastal areas of southern New England (except some areas with an onshore flow)
- Most of New Jersey
- Parts of southern Pennsylvania
- Southern Ohio
- Central and parts of southern Missouri
- Southern Indiana
- Southern Illinois (except for the far south)
- Parts of eastern Kansas
- Interior Maryland (except at the highest elevations)
- Lowland areas of West Virginia (except southwestern portion)
- Parts of the Arkansas Ozarks (due to higher elevations)
The western states of the central United States (namely Montana, Wyoming, parts of southern Idaho, parts of Colorado, western Nebraska, and western areas of North and South Dakota) have thermal regimes which fit the Dfa climate type, but are quite dry, and are generally grouped with the steppe (BSk) climates.
Outside of North America the Dfa climate type is present near the Black Sea in southern Ukraine, the Southern Federal District of Russia, Moldova, and parts of eastern Romania, but tends to be drier, or even semi-arid, in these places. Tohoku in Japan between Tokyo and Hokkaidō also has a climate with Köppen classification Dfa, but is wetter even than that part of North America with this climate type. A variant which has dry winters and hence much lower snowfall with monsoonal type summer rainfall is to be found in north-eastern China including coastal regions of the Yellow Sea and over much of the Korean Peninsula; it has the Köppen classification Dwa. Much of central Asia, northwestern China, and southern Mongolia have a thermal regime similar to that of the Dfa climate type, but these regions receive so little precipitation that they are more often classified as steppes (BSk) or deserts (BWk).
It appears nowhere within the Southern Hemisphere, which has no large landmasses so situated in the middle latitudes that allow the combination of hot summers and at least one month of sub-freezing temperatures.
Cities outside North America with this climate include:
- Rostov-on-Don, Russia
- Sapporo, Japan
- Beijing, China - Dwa
- Tianjin, China - Dwa
- Shenyang, China - Dwa
- Harbin, China - Dwa
- Pyongyang, North Korea - Dwa
- Seoul, South Korea - Dwa
Dfb/Dwb: Warm summer subtype
The warm summer version of a continental climate (Köppen: Dfb) generally lies north of the hot summer subtype. In North America, this version generally exists from about 44°N to 50°N latitude typically east of the 100th meridian. However, this version can be found as far north as 54°N in the Canadian Prairie Provinces and below 40°N in the high Appalachians. Areas featuring this subtype of the continental climate has an average temperature in its warmest month below 22°C. Summer temperatures in this zone typically average between 21–29 °C (70–84 °F) during the daytime and the average winter temperatures in the coldest month are generally far below the −3 °C (27 °F) isotherm.
It includes the following places:
- Central and Northern New England
- Northern, Central and Western New York
- Alleghany Plateau and Appalachians in Pennsylvania
- Northern Michigan (including the entire Upper Peninsula)
- Northern and central Wisconsin
- Northern and central Minnesota
- Eastern parts of The Dakotas
- Highest elevations of the central Appalachians
- Extreme northwestern New Jersey due to the Appalachians
- Some high-altitude areas of the Sierra Nevada,
- Some high-altitude areas of the Rocky Mountains
In Canada, it includes these areas:
- Most of Atlantic Canada
- Southern Quebec
- Most of Ontario except south of Toronto and far northern regions
- Southern Manitoba
- Central and southeastern Saskatchewan
- Central (latitudinal) Alberta
Some of the major cities in this zone:
- Albany, New York
- Bangor, Maine
- Buffalo, New York
- Burlington, Vermont
- Duluth, Minnesota
- Fargo, North Dakota
- Fredericton, New Brunswick
- Green Bay, Wisconsin
- Halifax, Nova Scotia
- Marquette, Michigan
- Montreal, Quebec
- Ottawa, Ontario
- Peterborough, Ontario
- Portland, Maine
- Quebec City, Quebec
- Rochester, New York
- Syracuse, New York
- Sault Ste. Marie, Ontario
- Sault Ste. Marie, Michigan
- Thunder Bay, Ontario
- Watertown, New York
- Winnipeg, Manitoba
- Worcester, Massachusetts
Such high-altitude locations as South Lake Tahoe, California and Aspen, Colorado in the western United States exhibit local Dfb climates. The south-central and southwestern Prairie Provinces also fits the Dfb criteria from a thermal profile, but its precipitation profile generally results in it being grouped in the BSk category.
Except for high-altitude locations, the only area in North America that could either be considered oceanic or warm-summer humid continental (coldest month averaging between 0°C and -3°C/27°F and 32°F) are portions of coastal southern New England where an onshore flow exists to moderate summer temperatures enough to average below 22°C (72°F).
It is also found in central Scandinavia. East central Europe (east of Germany and Hungary) is a warm summer subtype with less severe winters, more similar to the winters of the hot summer subtype found in eastern North America- the winters here are modified by the oceanic climate influence of western Europe.
The warm summer subtype is marked by mild summers, long cold winters and less precipitation than the hot summer subtype, however, short periods of extreme heat are not uncommon. Northern Japan has a similar climate.
Much of Mongolia and parts of southern Siberia have a thermal regime fitting this climate, but they have steppe- or desert-like precipitation, and so are not really considered to have a humid continental climate.
Countries with this climate:
- Eastern Poland
- Most of Ukraine
- Belarus
- Latvia, Lithuania, and Estonia
- Central European Russia
- Southern areas of Far Eastern (as dwb) and Siberian Federal Districts, Russia
- Northern North Korea (as dwb)
- Northern Japan
- Central regions of Sweden and southern part of Finland
- Southeast Norway
- Most of Slovakia
- Parts of Austria and Hungary
- Northeastern Romania
- Mountainous areas in the Balkans
- Italy's and Switzerland's Alps, between 1100 and 1600 meters (Western Alps) and between 900 and 1450 meters(Eastern and Central Alps)
In the Southern Hemisphere it exists in well-defined areas only in the Southern Alps of New Zealand and perhaps as isolated microclimates of the southern Andes of Chile and Argentina.
Cities with such climates outside North America include:
- Oslo, Norway
- Stockholm, Sweden
- Helsinki, Finland
- Moscow, Russia
- Saint Petersburg, Russia
- Warsaw, Poland
- Tallinn, Estonia
- Minsk, Belarus
- Kiev, Ukraine
- Kharkiv, Ukraine
- Riga, Latvia
- Vilnius, Lithuania
- Chişinău, Moldova
- Iaşi, Romania
- Dobbiaco, Italy
- Asahikawa, Japan
- Kushiro, Japan
- Vladivostok, Russia - Dwb
- Chongjin, North Korea - Dwb
Subarctic climate
Near 50°N in North America (except north of 55°N in Alberta, British Columbia and Saskatchewan) and eastern Asia (60°N or further north in Europe), the climate grades into a subarctic climate (Köppen: Dfc, Dwc), poleward of which the summers (seasons with temperatures above 10°C) are shorter than four months.
This climate appears nowhere in the Southern Hemisphere because of the complete absence of inland areas isolated from oceanic waters between 45° and 55° south latitude.
References
- ^ Peel, M. C. and Finlayson, B. L. and McMahon, T. A. (2007). "Updated world map of the Köppen-Geiger climate classification". Hydrol. Earth Syst. Sci. 11: 1633–1644. ISSN 1027-5606.
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: CS1 maint: multiple names: authors list (link) (direct: Final Revised Paper)