Humid continental climate
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The humid continental climate is a climate found over large areas of land masses 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. The seasonal temperature variance can be as great as 30-39° Celsius (55-70° Fahrenheit). The temperature difference between the warmest and coldest months increases as one moves further inland and away from the moderating influence of the ocean.
[edit] Dfa: Warm summer subtype
The warm summer (Köppen: Dfa) subtype of the humid continental climate, marked by hot (the warmest month has an average temperature in excess of 22°C), rainy summers and snowy winters lies on the eastern and midwestern portions of the United States and extreme southern Canada from the Atlantic to the 100th meridian west and from about 39°N to 44°N latitude; this area includes the following regions:
- Southern New England (Connecticut, Massachusetts, and Rhode Island)
- Most of New York state (except for the northern part and some highland areas in the southwest)
- Northern New Jersey
- Most of Pennsylvania (except for its southeastern region and some highland areas)
- Interior Maryland
- The higher elevations of:
- Western Virginia
- Kentucky
- Arkansas
- North Carolina (above 5000')
- Most of West Virginia (due to higher elevations)
- Most of Ohio
- Most of Indiana
- Most of Illinois
- Most of Missouri
- Iowa
- Eastern Nebraska
- Eastern Kansas
- Southern Minnesota
- Southern Wisconsin
- Southern Michigan
- Southern Ontario (south of and including Toronto)
Some of the major cities in this zone:
- Boston, Massachusetts
- Buffalo, New York
- Hartford, Connecticut
- Scranton, Pennsylvania
- Toronto, Ontario
- Cleveland, Ohio
- Detroit, Michigan
- Chicago, Illinois
- Milwaukee, Wisconsin
- Des Moines, Iowa
- Kansas City, Missouri
- Omaha, Nebraska
The 0°C isotherm (freeze line) or the -3°C isotherms (persistent snow line) are the possible lines dividing the humid continental and the humid subtropical climates, in between which are the following places (which are often included in the humid continental zone):
- St. Louis, Missouri
- Indianapolis, Indiana
- Cincinnati, Ohio
- Charleston, West Virginia
- Pittsburgh, Pennsylvania
- New York City
- Long Island
- Cape Cod
Th majority of the landmass covered by this climate type is present in North Amercian but it also exists in the Balkans and parts of Ukraine within Europe. A variant which has dry winters is to be found in northern China and Korea; it has the Köppen classification Dwa.
[edit] Dfb: Cool summer subtype
The cool summer subtype (Köppen: Dfb) lies north of the warm summer subtype; in North America, from about 44°N to 50°N in the east but places of adequate precipitation as far north as 54°N in the Canadian Prairie Provinces and below 40°N in the high Appalachians, separated by the 22°C isotherm for the warmest month from the Dfa climates (which passes near Minneapolis, Minnesota and Grand Rapids, Michigan).
It includes the following places:
- Northern New England
- Northern New York
- Northern Michigan
- Northern and central Wisconsin
- Northern and central Minnesota
- Eastern parts of The Dakotas
- Highest elevations of the central Appalachians
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:
- Halifax, Nova Scotia
- Portland, Maine
- Montreal, Quebec
- Ottawa, Ontario
- Sault Sainte Marie, Ontario
- Green Bay, Wisconsin
- Duluth, Minnesota
- Thunder Bay, Ontario
- Fargo, North Dakota
- Winnipeg, Manitoba
- Edmonton, Alberta
It is also found in central Scandinavia. East central Europe is a cool summer subtype with less severe winters, similar to the winters of the warm summer subtype - the winters here are modified by the oceanic climate influence of western Europe.
The cool summer subtype is marked by mild summers, long cold winters and less precipitation than the warm summer subtype, however, short periods of extreme heat are not uncommon. In this region, summers shorten and are cooler, and winters become longer and colder toward the north parts of this zone. Northern Japan has a similar climate.
Locations with such climates outside North America include:
- Oslo, Norway
- Stockholm, Sweden
- Helsinki, Finland
- Tallinn, Estonia
- Prague, Czech Republic
- Warsaw, Poland
- Saint Petersburg, Russia
- Minsk, Belarus
- Moscow, Russia
- Kiev, Ukraine
- Sapporo, Japan
A dry-winter variant (Köppen: Dwb) is to be found in northeastern China, northern Korea and the Southeastern region of Russian Far East, as at Vladivostok, Pyongyang, North Korea, and Harbin, China.
[edit] Subarctic climate
Near 50°N in North America (except north of 55°N in Alberta and British Columbia) 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.
Climate types under the Köppen climate classification |
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Class A: Tropical (Af) - Monsoon (Am) - Savanna (Aw, As) |
Class B: Arid (BWh, BWk) - Semi-arid (BSh, BSk) |
Class C: Humid subtropical (Cfa, Cwa) - Oceanic (Cfb, Cwb, Cfc) - Mediterranean (Csa, Csb) |
Class D: Humid continental (Dfa, Dwa, Dfb, Dwb) - Subarctic (Dfc, Dwc, Dfd) - High-altitude Mediterranean (Dsa, Dsb, Dsc) |
Class E: Polar (ET, EF) - Alpine (ETH) |