Climate means the usual condition of the temperature, humidity, atmospheric pressure, wind, rainfall, and other meteorological patterns in an area of the Earth's surface for a long time. In simple terms, climate is the average condition for about thirty years. Climate and weather are different: weather is the day to day conditions in the atmosphere.
- Polar climate (also called boreal climate), has long, usually very cold winters, and short summers. For example, near the north and south poles.
- Temperate climates have four seasons. Some of the countries which have a temperate climate are: most of the European countries.
- Deserts are very dry. They just have one or two seasons such as: Saudi Arabia and many African countries.
- Tropical climates have warm temperature and only two seasons; wet and dry. An example of a place with a tropical climate is the Amazon Rainforest in Brazil.
- The Mediterranean climate is usually hot and dry in summer, and is cool and wet in winter. An example of a country with a Mediterranean climate is Spain.
The latitude, ground, and height can change the climate of a location. It is also important to note if oceans or other large bodies of water are nearby. Climates are most commonly classified by temperature and precipitation. The most commonly used classification was the Köppen climate classification, first made by Wladimir Köppen. The Thornthwaite system, which was used from 1948, not only uses temperature and precipitation information, but evapotranspiration too. This makes it useful for studying how many different kinds of animal species there are, and about the things that could happen when climates change. The Bergeron and Spatial Synoptic Classification systems focus more on where the air masses which help make climates come from.
- C. W. Thornthwaite, "An Approach Toward a Rational Classification of Climate", Geographical Review, 38:55-94, 1948