Climate

A region’s climate is its general pattern of weather over a long period of time. The weather in a region may, at some times of the year, change almost from day to day. But the climate remains similar year after year. For example, a seaside town in southern Italy may have a week of hot, dry days, followed by a dull, warm day, and then a cold, wet day. But these rapid weather changes do not affect the general climate of the place. Southern Italy has a 'warm temperate' climate, which means that in general it has hot, dry summers and mild, wet winters.
No matter what part of the world we live in, our way of life depends on the climate. How we dress, what we eat, the kind of house we live in, all may be governed by climate. Factors having most influence on climate include the amount and intensity of sunshine, the altitude (height above sea level), and the amount of rainfall.
The factor that has the greatest effect on the climate of a place is the amount and intensity of sunshine it receives. Different parts of the world receive different amounts of heat from the Sun. This unequal heating of the Earth’s surface results in differences in temperature and pressure in various places, and is responsible for movements of air masses. As a rule, the heat from the Sun is greatest at the Equator and decreases towards the Poles. This is due to the curvature of the Earth which makes a similar amount of the Sun’s rays spread over a greater area near the Poles than near the Equator.
The Earth can be divided, broadly, into a number of temperature zones: hot (equatorial and tropical), warm temperate, cool temperate, cold, and polar. But these are not exact zones stretching from the Equator to the Poles. They are modified by, for instance, the effect of the oceans. Water heats up less rapidly than land, but keeps its warmth longer. Thus the oceans cool coastal regions of the continents in summer and warm them in winter. In contrast, regions far from the sea tend to have hot summers and cold winters. In parts of Siberia, far inland, the annual temperature range is more than 55° C. (about 100 F.).
Altitude affects climate because the air is thinner at higher altitudes. The temperature drops about 1/2° C. (about 1 Degree F.) for each 300 feet up. Mount Chimborazo in Ecuador, straddles the Equator, but it has a permanent cap of snow.
Rainfall is a major feature of climate. The wettest regions are generally those reached by winds that have blown for long distances across seas and oceans. Hilly regions tend to receive more rain than lowlands, particularly on the slopes facing the winds. Mountains force winds to rise, and air becomes cooler as it rises. Cool air cannot hold as much moisture as warm air, and as a result clouds form and rain falls.
Ocean currents also affect climate. For example, the coast of Norway remains free of ice because it is warmed by the waters of the North Atlantic Drift, an extension of the Gulf Stream. But coastal waters in Labrador are frozen in winter even though they are 15 farther south.

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