Humid continental climate

A humid continental climate is a climatic region defined by Russo-German climatologist Wladimir Köppen in 1900,^[1] typified by four distinct seasons and large seasonal temperature differences, with warm to hot (and often humid) summers, and cold (sometimes severely cold in the northern areas) and snowy winters. Precipitation is usually distributed throughout the year, but often these regions do have dry seasons. The definition of this climate in terms of temperature is as follows: the mean temperature of the coldest month must be below 0 °C (32.0 °F) or −3 °C (26.6 °F) depending on the isotherm,^[2] and there must be at least four months whose mean temperatures are at or above 10 °C (50 °F). In addition, the location in question must not be semi-arid or arid. The cooler Dfb, Dwb, and Dsb subtypes are also known as hemiboreal climates.

Humid continental climate worldwide, utilizing the Köppen climate classification

  Dsa

  Dsb

  Dwa

  Dwb

  Dfa

  Dfb

Humid continental climates are generally found between latitudes 40° N and 60° N,^[3] within the central and northeastern portions of North America, Europe, and Asia. They are rare and isolated in the Southern Hemisphere, due to the larger ocean area at that latitude, smaller land mass, and the consequent greater maritime moderation. In the Northern Hemisphere, some of the humid continental climates, typically in Hokkaido, Northern Honshu, Sakhalin island, northeastern mainland Europe, Scandinavia, Nova Scotia, and Newfoundland are closer to the sea and heavily maritime-influenced and comparable to oceanic climates, with relatively cool summers and winters being just below the freezing mark (too cold for such a classification).^[4] More extreme and inland humid continental climates, sometimes known as "hyper-continental" climates, are found in northeast China, southern Siberia, the Canadian Prairies, and the Upper Midwest, where temperatures in the winter resemble those of subarctic climates but have warmer and longer summers. In east-central China, North Korea, Eastern Europe, the Great Lakes region of the American Midwest, New England, and south-central and south-eastern parts of Canada the climate combines hotter summer maxima and colder winters than the marine-based variety and is less extreme than the most inland variety, with similarities to the adjacent humid subtropical climate but with colder winters which preclude such classifications.^[5]

Definition

 

The snowy city of Sapporo, Japan, has a humid continental climate (Köppen Dfa).

Using the Köppen climate classification, a climate is classified as humid continental when the temperature of the coldest month is below 0 °C [32.0 °F] or −3 °C [26.6 °F] and there must be at least four months whose mean temperatures are at or above 10 °C (50 °F).^[6] These temperatures were not arbitrary. In Europe, the −3 °C (27 °F) average temperature isotherm (line of equal temperature) was near the southern extent of winter snowpack. In the United States, it is more common to use the 0 °C [32.0 °F] isotherm instead. The 10 °C (50 °F) average temperature was found to be roughly the minimum temperature necessary for tree reproduction and growth.^[7] Wide temperature ranges are common within this climate zone.^[8]

Second letter in the classification symbol defines seasonal rainfall as follows: ^[6]

• s: A dry summer—the driest month in the high-sun half of the year (April to September in the Northern Hemisphere, October to March in the Southern Hemisphere) has less than 30 millimetres (1.18 in)/40 millimetres (1.57 in) of rainfall and has exactly or less than 1⁄3 the precipitation of the wettest month in the low-sun half of the year (October to March in the Northern Hemisphere, April to September in the Southern Hemisphere).
• w: A dry winter—the driest month in the low-sun half of the year has exactly or less than one‑tenth of the precipitation found in the wettest month in the summer half of the year.
• f: No dry season—does not meet either of the alternative specifications above; precipitation and humidity are often high year-round.

while the third letter denotes the extent of summer heat:^[6]

• a: Hot summer, warmest month averages at least 22 °C (71.6 °F),
• b: Warm summer, warmest month averages below 22 °C (71.6 °F) but at least four months averages above 10 °C (50.0 °F).

Associated precipitation

Within North America, moisture within this climate regime is supplied by the Great Lakes, Gulf of Mexico and adjacent western subtropical Atlantic.^[9] Precipitation is relatively well distributed year-round in many areas with this climate (f), while others may see a marked reduction in wintry precipitation,^[7] which increases the chances of a wintertime drought (w).^[10] Snowfall occurs in all areas with a humid continental climate and in many such places is more common than rain during the height of winter. In places with sufficient wintertime precipitation, the snow cover is often deep. Most summer rainfall occurs during thunderstorms,^[7] and in North America and Asia an occasional tropical system. Though humidity levels are often high in locations with humid continental climates, the "humid" designation means that the climate is not dry enough to be classified as semi-arid or arid.

Vegetation

 

Mixed forest in Vermont during autumn

By definition, forests thrive within this climate. Biomes within this climate regime include temperate woodlands, temperate grasslands, temperate deciduous or evergreen forests,^[9] coniferous forests, and coniferous swamps.^[11] Within wetter areas, maple, spruce, pine, fir, and oak can be found. Fall foliage is noted during the autumn of deciduous forests.^[7]

Hot summer subtype

 

Regions with hot-summer humid continental climates

Windsor, Canada
Climate chart (explanation)
J F M A M J J A S O N D     62     0 −7     62     1 −6     70     7 −2     83     14 4     89     20 10     86     26 15     89     28 18     73     27 17     94     23 13     73     16 7     80     9 1     74     2 −4 █ Average max. and min. temperatures in °C █ Precipitation totals in mm Source: ^[12]
Imperial conversion J F M A M J J A S O N D     2.4     31 19     2.4     34 21     2.8     44 28     3.3     57 39     3.5     69 49     3.4     78 60     3.5     83 64     2.9     80 63     3.7     73 55     2.9     60 44     3.1     48 35     2.9     36 24 █ Average max. and min. temperatures in °F █ Precipitation totals in inches

Shenyang, China
Climate chart (explanation)
J F M A M J J A S O N D     6.9     −5 −17     8.6     0 −12     21     7 −4     40     17 5     53     23 12     93     28 17     174     29 21     169     29 19     65     24 12     39     16 4     20     6 −5     10     −2 −13 █ Average max. and min. temperatures in °C █ Precipitation totals in mm Source: China Meteorological Administration ^[13]
Imperial conversion J F M A M J J A S O N D     0.3     23 2     0.3     31 11     0.8     45 25     1.6     62 40     2.1     74 53     3.6     82 63     6.8     84 69     6.7     83 67     2.5     75 54     1.6     61 40     0.8     42 24     0.4     28 9 █ Average max. and min. temperatures in °F █ Precipitation totals in inches

A hot summer version of a continental climate features an average temperature of at least 22 °C (71.6 °F) in its warmest month.^[14] Since these regimes are restricted to the Northern Hemisphere, the warmest month is usually July or August. High temperatures in the warmest month tend to be in the high 20s or low 30s °C (80s or low 90s °F), while average January afternoon temperatures are near or well below freezing. Frost-free periods normally last 4–7 months within this climate regime.^[7]

Within North America, this climate includes portions of the central and eastern United States from east of 100°W to south of about the 42°N to the Atlantic. Precipitation increases further eastward in this zone and is less seasonally uniform in the west. The western states of the western United States (namely Montana, Wyoming, parts of southern Idaho, most of Lincoln County in Eastern Washington, parts of Colorado, parts of Utah, isolated parts of northern New Mexico, western Nebraska, and parts of western 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. In the eastern United States Pennsylvania, Ohio, Illinois, Indiana, southern New York, southern Connecticut, and southern Rhode Island fall into the hot summer Humid Continental climate.

In the Eastern Hemisphere, this climate regime is found within interior Eurasia and east-central Asia. Within Europe, the Dfa climate type is present near the Black Sea in southern Ukraine, the Southern Federal District of Russia, southern Moldova, Serbia, parts of southern Romania, and Bulgaria,^[15][16] but tends to be drier and can be even semi-arid in these places. In East Asia, this climate exhibits a monsoonal tendency with much higher precipitation in summer than in winter, and due to the effects of the strong Siberian High much colder winter temperatures than similar latitudes around the world, however with lower snowfall, the exception being western Japan with its heavy snowfall. Tōhoku, between Tokyo and Hokkaidō and Western coast of Japan 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 relatively lower snowfall with monsoonal type summer rainfall is to be found in northern China including Manchuria and parts of North China, south-east Russia, and over much of the Korean Peninsula; it has the Köppen classification Dwa. Much of central Asia, northwestern China, and southern Mongolia has 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).

Dsa climates are rare; they are generally restricted to elevated areas adjacent to Mediterranean climate regions with a Csa climate well inland to ensure hot summers and cold winters. They are generally found in the highly elevated areas of south-eastern Turkey (Hakkâri), north-western Iran, northern Iraq, parts of Central Asia, and parts of the Intermountain West in the United States.

This climate zone does not exist at all in the southern hemisphere, where the only landmass that enters the upper-middle latitudes, South America, tapers too much to have any place that gets the combination of snowy winters and hot summers. Marine influences preclude Dfa, Dwa, and Dsa climates in the southern hemisphere.

Warm summer subtype

 

Regions with warm-summer humid continental climates

Moscow, Russian Federation
Climate chart (explanation)
J F M A M J J A S O N D     53     −4 −9     44     −3 −9     39     3 −4     37     12 2     61     19 8     78     22 12     84     25 15     78     23 13     66     16 8     70     9 3     52     2 −2     51     −2 −7 █ Average max. and min. temperatures in °C █ Precipitation totals in mm Source: pogoda.ru.net
Imperial conversion J F M A M J J A S O N D     2.1     25 16     1.7     27 16     1.5     37 24     1.5     53 36     2.4     66 47     3.1     72 54     3.3     76 59     3.1     73 55     2.6     62 46     2.8     48 37     2     35 28     2     28 20 █ Average max. and min. temperatures in °F █ Precipitation totals in inches

Erzurum, Turkey
Climate chart (explanation)
J F M A M J J A S O N D     16     −4 −16     19     −2 −15     35     4 −8     56     12 −1     72     18 3     42     23 6     22     28 10     17     29 10     23     24 4     47     16 0     26     7 −6     21     −1 −12 █ Average max. and min. temperatures in °C █ Precipitation totals in mm Source: mgm.gov.tr
Imperial conversion J F M A M J J A S O N D     0.6     25 3     0.7     28 6     1.4     39 19     2.2     54 31     2.8     64 38     1.7     73 43     0.9     82 50     0.7     83 50     0.9     75 40     1.9     62 33     1     45 21     0.8     30 10 █ Average max. and min. temperatures in °F █ Precipitation totals in inches

Winnipeg, Canada
Climate chart (explanation)
J F M A M J J A S O N D     20     −11 −21     14     −8 −18     25     −1 −11     30     11 −2     57     19 5     90     23 11     80     26 14     77     25 12     46     19 6     38     11 −1     25     −1 −9     22     −9 −18 █ Average max. and min. temperatures in °C █ Precipitation totals in mm Source: Environment Canada^[17]
Imperial conversion J F M A M J J A S O N D     0.8     12 −7     0.6     17 −1     1     31 13     1.2     52 28     2.2     65 40     3.5     74 51     3.1     79 56     3     78 54     1.8     66 44     1.5     51 31     1     31 15     0.9     17 0 █ Average max. and min. temperatures in °F █ Precipitation totals in inches

Halifax, Canada
Climate chart (explanation)
J F M A M J J A S O N D     139     0 −8     110     0 −8     133     4 −4     118     9 1     119     14 6     112     20 11     110     23 14     96     23 15     109     19 12     124     13 6     151     8 2     145     3 −4 █ Average max. and min. temperatures in °C █ Precipitation totals in mm Source: Environment Canada^[18]
Imperial conversion J F M A M J J A S O N D     5.5     32 17     4.3     33 19     5.2     38 25     4.6     48 34     4.7     58 42     4.4     67 51     4.3     74 58     3.8     74 59     4.3     67 53     4.9     56 44     5.9     47 35     5.7     37 24 █ Average max. and min. temperatures in °F █ Precipitation totals in inches

Yuzhno-Sakhalinsk
Climate chart (explanation)
J F M A M J J A S O N D     56     −6 −17     38     −5 −17     52     0 −10     57     7 −3     66     14 3     64     18 8     92     21 12     107     22 14     102     19 9     102     13 2     75     4 −5     71     −4 −13 █ Average max. and min. temperatures in °C █ Precipitation totals in mm Source: ユジノ・サハリンスクの気候^[19]
Imperial conversion J F M A M J J A S O N D     2.2     21 2     1.5     23 1     2     32 13     2.2     44 27     2.6     57 37     2.5     64 46     3.6     70 54     4.2     72 56     4     67 48     4     55 35     3     38 23     2.8     26 8 █ Average max. and min. temperatures in °F █ Precipitation totals in inches

Nosappu
Climate chart (explanation)
J F M A M J J A S O N D     19     −1 −6     15     −1 −7     37     2 −4     54     7 0     83     11 4     94     14 7     108     18 11     116     20 14     131     19 13     103     15 8     75     9 2     49     2 −3 █ Average max. and min. temperatures in °C █ Precipitation totals in mm Source: Japan Meteorological Agency^[20]
Imperial conversion J F M A M J J A S O N D     0.7     31 21     0.6     30 20     1.5     35 25     2.1     44 32     3.3     52 39     3.7     57 45     4.2     64 52     4.6     69 58     5.1     67 56     4.1     59 47     3     48 36     1.9     36 26 █ Average max. and min. temperatures in °F █ Precipitation totals in inches

Also known as Hemiboreal climate, areas featuring this subtype of the continental climate have an average temperature in the warmest month below 22 °C (72 °F). Summer high temperatures in this zone typically average between 21–28 °C (70–82 °F) during the daytime and the average temperatures in the coldest month are generally well or far below the −3 °C (27 °F) (or 0 °C (32.0 °F)) isotherm. Frost-free periods typically last 3–5 months. Heat spells lasting over a week are rare.^[7]

The warm summer version of the humid continental climate covers a much larger area than the hot subtype. In North America, the climate zone covers from about 42°N to 50°N latitude mostly east of 100°W, including parts of Southern Ontario, the southern half of Quebec, The Maritimes, and Newfoundland, as well as the northern United States from eastern North Dakota east to Maine. However, it can be found as far north as 54°N, and further west in the Canadian Prairie Provinces^[21] and below 40°N in the high Appalachians. In Europe, this subtype reaches its most northerly latitude in Bodø at the 67°N.^[22]

High-altitude locations such as Aspen, Colorado and Los Alamos, New Mexico 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 because of semi-arid precipitation portions of it are grouped into the BSk category. ^[23]

In Europe, it is found in much of Central Europe: Germany (in the east and southeast part of the country), Austria (generally below 700 m (2,297 ft)), Poland, Czech Republic, Slovakia, Hungary (generally above 100 m (328 ft)), Croatia (mostly Slavonia region), in much of Eastern Europe: Ukraine (the whole country except the Black Sea coast), Belarus, Russia (mostly central part of European Russia), south and central parts of the Nordic countries not bathed by the Atlantic Ocean or North Sea: Sweden (historical regions of Svealand and Götaland), Denmark, Finland (south end, including the three largest cities),^[16] Norway (most populated area),^[6], all Baltic States: Estonia, Latvia, Lithuania and also in parts of: Romania (generally above 100 m (328 ft)), Bosnia and Herzegovina, Turkey and in the Cairngorm Mountains of Scotland, (generally above 100 m (328 ft)).^[15][24] It has little warming or precipitation effects from the northern Atlantic.^[16] The cool 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.^[25]

In the Southern Hemisphere, it exists in well-defined areas only in the Southern Alps of New Zealand,^[26] in the Snowy Mountains of Australia in Kiandra, New South Wales^[27] and the Andes Mountains of Argentina and Chile.^[28]

Use in climate modeling

Since climate regimes tend to be dominated by vegetation of one region with relatively homogenous ecology, those that project climate change remap their results in the form of climate regimes as an alternative way to explain expected changes.^[1]

See also

• Continental climate
• Subarctic climate
• Hemiboreal

References

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2. Kottek, Markus; Grieser, Jürgen; Beck, Christoph; Rudolf, Bruno; Rubel, Franz (2006). "World Map of the Köppen-Geiger climate classification updated". Meteorologische Zeitschrift. 15 (3): 259–263. Bibcode:2006MetZe..15..259K. doi:10.1127/0941-2948/2006/0130.
3. Béla Berényi. Cultivated Plants, Primarily As Food Sources -- Vol II -- Fruit in Northern Latitudes (PDF). Encyclopedia of Life Support Systems. p. 1. Retrieved 2015-02-23.
4. "Halifax, Nova Scotia Temperature Averages". Weatherbase. Retrieved 7 February 2015.
5. "Milwaukee, Wisconsin Temperature Averages". Weatherbase. Retrieved 7 February 2015.
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13. (in Chinese). China Meteorological Administration. Archived from the original on 2013-09-21. Retrieved 2010-05-04.
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15. Joseph Hobbs (2012). Fundamentals of World Regional Geography. Cengage Learning. p. 76. ISBN 978-1-285-40221-5.
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18. "Halifax Stanfield INT'L A, Nova Scotia". Canadian Climate Normals 1981–2010. Environment Canada. 2011-10-31. Retrieved May 8, 2014.
19. "気候テーブル。ユジノ・サハリンスクのデータ。". pogodaiklimat.ru. 2011-10-31. Retrieved May 8, 2014.
20. "納沙布 平年値（年・月ごとの値） 主な要素". Japan Meteorological Agency. 2011-10-31. Retrieved March 6, 2022.
21. Williams, B. W.; Proctor, H. C.; Clayton, T. (2011). "Range Extension of the Northern Crayfish, Orconectes Virilis (decapoda, Cambaridae), in the Western Prairie Provinces of Canada". Crustaceana. 84 (4): 451–460. ISSN 0011-216X.
22. https://www.yr.no/en/statistics/Bodø - Normal (mean monthly temperatures 1991-2020) and observed temperatures from met.no
23. "Warm-summer Humid Continental Climate (Dfb) | SKYbrary Aviation Safety". skybrary.aero. Retrieved 2023-10-19.
24. Erdoğan Bölük (2016). Köppen İklim Sınıflandırmasına göre Türkiye İklimi (PDF). Meteoroloji Genel Müdürlüğü. p. 18.
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27. Crosbie, R. S.; Pollock, D. W.; Mpelasoka, F. S.; Barron, O. V.; Charles, S. P.; Donn, M. J. (2012-09-18). "Changes in Köppen-Geiger climate types under a future climate for Australia: hydrological implications". Hydrology and Earth System Sciences. Copernicus GmbH. 16 (9): 3341–3349. Bibcode:2012HESS...16.3341C. doi:10.5194/hess-16-3341-2012. ISSN 1607-7938.
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