Temperate

2007 Concise Encyclopedia. Related subjects: General Physics

In geography, temperate latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally subtle, warm or cool, rather than extreme, burning hot or freezing cold. However, a temperate climate can have very unpredictable weather. One day it may be sunny, the next it may be raining, and after that it may be cloudy. These erratic weather patterns occur in summer as well as winter.

The north temperate zone extends from the Tropic of Cancer at about 23.5 degrees north latitude to the Arctic Circle at about 66.5 degrees north latitude. The south temperate zone extends from the Tropic of Capricorn at about 23.5 degrees south latitude to the Antarctic Circle at about 66.5 degrees south latitude.

Within these borders there are many individual climate types, which are generally grouped into two categories: continental and maritime.

The maritime climate is clearly affected by the oceans, which help to sustain somewhat stable temperatures throughout the year. In the temperate zones, the prevailing winds are to the west, the western edge of temperate continents most commonly experience this maritime climate. Such regions include Western Europe, especially the UK, and western North America at latitudes between 40° and 60° north (65°N in Europe).

The continental climate is usually situated inland, with warmer summers and colder winters. The large land mass increases its effects on heat reception and loss. In North America, the Rocky Mountains act as a climate barrier to the maritime air blowing from the west, creating a continental climate to the east. In Europe, the maritime climate is able to stabilize temperatures further inland, because the major mountain range - the Alps - is oriented east-west.

The idea of a temperate "zone" was first hypothesized by the ancient Greek scholar Aristotle. He said that the earth was divided into three types of climatic zones, based on their distance from the equator.

Thinking that the area near the equator was too hot for habitation, Aristotle dubbed the region around the equator (from 23.5° N to 23.5° S) as the "Torrid Zone." He reasoned that from the Arctic Circle to the pole was permanently frozen. He called this uninhabitable zone the "Frigid Zone." The only area that Aristotle believed was livable was the "Temperate Zone", lying between the "Frigid Zone" and the "Torrid Zone". One of the reasons Aristotle believed that the Temperate Zone was the best for life could come from the fact that he lived in that zone.

As knowledge of the earth's geography improved a second "Frigid Zone" was discovered south of the equator around the Antarctic and a second "Temperate Zone" was discovered south of the equator.

Aristotle's map was vastly oversimplified, although the general idea was correct. Today, the most commonly used climate map is one developed by German climatologist and amateur botanist Wladimir Köppen (1846-1940) which divides the world into six major climate regions, based on average annual precipitation, average monthly precipitation, and average monthly temperature.