Editing Microthermal

{{More citations needed|date=April 2022}}
In [[climatology]], the term '''microthermal''' is used to denote the [[continental climate]]s of [[Eurasia]] and [[North America]].

==Etymology==
The word ''microthermal'' is derived from two [[Greek language|Greek]] words meaning "small" and "heat". This is misleading, however, since the term is intended to describe only the [[temperature]] conditions that prevail during the [[winter]] months, rather than those of the entire year.<ref>{{Citation |title=microthermal |date=2019-03-14 |url=https://en.wiktionary.org/w/index.php?title=microthermal&oldid=51810680 |work=Wiktionary |language=en |access-date=2022-04-06}}</ref>

==Characteristics==
Under the original [[Köppen climate classification]], all places with an average temperature in their coldest month that is colder than -3&nbsp;°C (26,4 F), are said to have a microthermal climate. The isotherm of -3&nbsp;°C for the coldest monthly mean temperature, was observed to be the line where the climate was likely cold enough to support a fixed period of continuous [[snow]] cover every year.{{citation needed|date=April 2022}} In recent usage, an isotherm of 0°C (32°F) is commonly used instead. Either definition places almost all of the world's microthermal climates in the [[Northern Hemisphere]], as the absence of broad land masses at upper-middle latitudes in the [[Southern Hemisphere]] precludes, with few exceptions, the existence of such temperature conditions there due to the sea moderating temperatures.<ref>{{Cite web |title=why are continental climates found in the northern hemisphere but not in the southern hemisphere - Lisbdnet.com |url=https://lisbdnet.com/why-are-continental-climates-found-in-the-northern-hemisphere-but-not-in-the-southern-hemisphere/ |access-date=2022-04-06 |language=en-US}}</ref>

Microthermal climates are typically subdivided into three categories based on the temperature characteristics of the summer season.  The southernmost of the three is frequently referred to as the '''temperate continental''' climate, and has hot summers &mdash; that is to say, at least one month has an average temperature of 22&nbsp;°C (71.6&nbsp;°F) or above.  The middle zone is often labelled '''[[hemiboreal]]''', and no summer month there has an average temperature as warm as 22&nbsp;°C, but at least four months will still average at 10&nbsp;°C (50&nbsp;°F) or higher.  The northernmost of the three microthermal zones is the subarctic, or '''[[boreal ecosystem|boreal]]''' zone; there only one to three months will have average temperatures above 10&nbsp;°C, bordering [[Polar regions of Earth|polar regions]].<ref>{{Cite web |date=2021-12-20 |title=Continental Climate: What Is & Definition |url=https://www.tomorrow.io/weather/blog/continental-climate/ |access-date=2022-04-06 |website=Tomorrow.io Weather Blog |language=en}}</ref><ref>{{Cite web |last=Society |first=National Geographic |date=2017-09-26 |title=All About Climate |url=http://www.nationalgeographic.org/article/all-about-climate/ |access-date=2022-04-06 |website=National Geographic Society |language=en}}</ref>

==Boundaries==
In [[North America]], microthermal climates start north of Boston along the Atlantic seaboard then westward to just below the Great Lakes to the Midwest, the line then moves southward below the Dakotas, through the west near 40 latitude at the eastern edge of the [[Rocky Mountains]], then curving northward near the lowlands of the [[Pacific Ocean|Pacific]] coast, reaching the Pacific Ocean just south of [[Juneau, Alaska]].  In [[Asia]], the latitude at which these climates begin is several degrees farther south influence of the vast Siberian anticyclone, or high-pressure system, and in continental [[Europe]] the line actually runs longitudinally rather than latitudinally, cutting through central [[Poland]] after beginning north of the [[Arctic Circle]] along the Norwegian coast, thereafter moving diagonally across [[Scandinavia]].

The boundary between the microthermal and polar climate zones is farthest north in western Europe (actually within the Arctic Circle there), and farthest south near the northeast coast of Canada (at about 56° North latitude on the central coast of [[Labrador]]); it then trends northward across [[Canada]] before dropping south again as it courses through [[Alaska]].  Throughout most of [[Siberia]], the boundary tends to follow the Arctic Circle fairly closely.

In addition to having various summer temperature regimes, microthermal climates also differ from one another in how much [[precipitation (meteorology)|precipitation]] they receive &mdash; such climates may be [[humid]], [[Semi-arid climate|semiarid]] or [[arid]].  Most of the [[Gobi Desert|Turkestan-Gobi]] desert system has an arid microthermal climate, while the best-known example of the semiarid microthermal climate can be found in the "[[steppe]]s of [[Central Asia]]" immortalized by [[Russia]]n [[european classical music|classical music]] [[composer]] [[Alexander Borodin]].

==References==
{{Reflist}}

==Sources==
[http://www.fao.org/docrep/x5375e/x5375e02.htm Unasylva - Vol.9, No. 2 - Climatic classification in forestry]

==See also==

*[[Megathermal]]
*[[Mesothermal]]
*[[Humid continental]]
*[[Subarctic]]

[[Category:Climate and weather classification systems]]