humid continental climate


A humid continental climate (Köppen climate classification prefix D) is a climatic region typified by large seasonal temperature differences, with warm to hot (and often humid) summers, and cold (sometimes severely cold) winters.

Precipitation is relatively well-distributed year-round in many areas, while others may see a marked reduction in wintry precipitation and even a wintertime drought. Snowfall, regardless of average seasonal totals, occurs in all areas with a humid continental climate and is in many such places 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 and a very occasional tropical system. Though humidity levels are often high in locations with humid continental climates, it is important to note that the "humid" designation only denotes that the climate is not dry enough to be classified semi-arid or arid, not that humidity levels are necessarily high.

Humid continental climates tend to be found above 40° N latitude, and within the central and northeastern portions of North America, Europe, and Asia. They are much less commonly found in the Southern Hemisphere due to the larger ocean area at that latitude and thus greater maritime moderation.

The Köppen definition of this climate, regarding temperature, is as follows: the mean temperature of the coldest month be below (some climatologists prefer to use the freezing mark), and that there be at least four months with mean temperatures at or above . In addition, the location in question must not be semi-arid or arid.

Contents

Explanation of Lettering

Under Köppen, the following variants of this climate are possible:

  • The second letter
    • w: a dry winter —— the driest winter month has at most 1/10th of the precipitation found in the wettest summer month.
    • s: a dry summer —— the driest summer month has at most of rainfall and has at most 1/3 the precipitation of the wettest winter month.
    • f: fails to meet the above qualifications.
  • The third letter
    • a: Warmest month averages above
    • b: Fails to meet a, but still there are at least four months above .

Dfa/Dwa/Dsa: Hot (or very warm) summer subtype

A hot (or very warm) version of a continental climate features an average temperature of at least in its warmest month. The warmest month is usually July, though it some cases it can be in August. Average July afternoon temperatures in this zone generally average above and up to while the average temperature of the coldest month is or colder. In some instances, the average temperature of the coldest month can be far below . In Europe, it is found a land largely wrapping the Black Sea coastline from Romania northeast into Ukraine and the lower Don river estuary in Russia. In Asia, around the Caspian Sea in Russia, Kazakstan, in parts of Iran, Turkey and parts of Kashmir in India. It covers a swath of Northestern China, including its capital Bejing and Jilin province, parts of North Korea and micro regions of Japan. In East Asia, this climate exhibits a monsoonal tendency with much higher summer precipitation.

Within North America it includes parts of southern New England and the Middle Atlantic states, much of the Midwestern United States and small parts of Southern Ontario, Canada from the Atlantic to the 100th meridian and in the general range of between 39°N to 44°N latitude (with a larger north-south spread in the western portion due to the lack of maritime influences; precipitation increases further eastward in this zone and is less seasonally uniform in the west; this area includes the following regions:

Some of the major North American cities in this zone:

The isotherm (freeze line) or the 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 . In between these lines are the following places:

Some regions in this zone:

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, southern Moldova, and parts of southern and western 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 in this climate zone include:

Dfb/Dwb/Dsb: Warm summer subtype

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 44°N to 50°N latitude mostly east of the 100th meridian. However, it can be found as far north as 54°N, and further west in the Canadian Prairie Provinces and below 40°N in the high Appalachians. In Europe this subtype reaches its most northern latitude at nearly 61°N. Areas featuring this subtype of the continental climate have an average temperature in its warmest month below 22°C. Summer high temperatures in this zone typically average between during the daytime and the average winter temperatures in the coldest month are generally far below the isotherm.

It includes the following places:

In Canada, it includes these areas:

Some of the major cities in this zone:

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 because of semi-arid precipitation its grouped into 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 (32°F) and -3°C (26.6°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).

In Europe, it is also found in central Scandinavia, but in eastern Central Europe (eastern Austria, eastern Germany, Poland, Czech Republic, Slovakia, Hungary, northern Romania) 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:

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:

Charts of Selected Cities with Humid Continental Climates

Chicago
Climate chart (explanation)
J F M A M J J A S O N D
average max. and min. temperatures in °C
precipitation totals in mm
source: NCDC

Montreal
Climate chart (explanation)
J F M A M J J A S O N D
average max. and min. temperatures in °C
precipitation totals in mm
source: Environment Canada

Moscow
Climate chart (explanation)
J F M A M J J A S O N D
average max. and min. temperatures in °C
precipitation totals in mm
source: pogoda.ru.net

Beijing
Climate chart (explanation)
J F M A M J J A S O N D
average max. and min. temperatures in °C
precipitation totals in mm
source: CMA
Sapporo
Climate chart (explanation)
J F M A M J J A S O N D
average max. and min. temperatures in °C
precipitation totals in mm
source: JMA
Vladivostok
Climate chart (explanation)
J F M A M J J A S O N D
average max. and min. temperatures in °C
precipitation totals in mm
source: Pogoda.ru.net
Almaty
Climate chart (explanation)
J F M A M J J A S O N D
average max. and min. temperatures in °C
precipitation totals in mm
source: Pogoda.ru.net

See also

References

[[|v]] · [[|d]] · eClimate types under the Köppen climate classification
Class A
Class B
Class C
Class D
Class E