Weather and climate
There is often confusion between weather and climate.
Weather is the condition of the atmosphere at a particular place over a short period of time. For example, on a particular day in Trinidad, the weather is warm in the afternoon. But later in the day, when there are clouds blocking Sun's rays, the weather would become cooler.
Climate refers to the weather pattern of a place over a long period, maybe 30 years or more, long enough to yield meaningful averages (). For example, although the weather in Pakistan may be cool and dry today, Pakistan's climate is hot most of the time.
There are several elements that make up the weather and climate of a place. The major of these elements are five: temperature, pressure, wind, humidity, and rain. Analysis of these elements can provide the basis for forecasting weather and defining its climate. These same elements make also the basis of climatology study, of course, within a longer time scale rather than it does in meteorology.
- Temperature is how hot or cold the atmosphere is, how many degrees it is above or below freezing . Temperature is a very important factor in determining the weather, because it influences or controls other elements of the weather, such as precipitation, humidity, clouds and atmospheric pressure.
- Humidity is the amount of water vapor in the atmosphere.
- Precipitation is the product of a rapid condensation process (if this process is slow, it only causes cloudy skies). It may include snow, hail, sleet, drizzle, fog, mist and rain.
- Atmospheric pressure (or air pressure) is the weight of air resting on the earth's surface. Pressure is shown on a weather map, often called a synoptic map, with lines called isobars.
- Wind is the movement of air masses, especially on the Earth's surface.
- Arthur Newell Strahler. Physical Geography. New York: John Wiley & Sons, 1960, Second Edition, p. 185
- F. J. Monkhouse. A Dictionary of Geography. London: Edward Arnold (Publishers) Ltd., 1978