The temperature, atmospheric pressure, winds and precipitation are main elements of weather have an important effect on our lives. For example the houses we construct, the clothes we wear and the food we prefer mainly depend on weather and climatic conditions.
Water vapour is a highly variable component of the atmosphere. Its proportion varies from zero to four percent by volume of the atmosphere.
Temperature, pressure, wind, humidity and precipitation, interact with each other and known as the elements of both weather and climate.
Weather is the atmospheric condition of a place for a short duration with respect to its one or more elements.
Season: Season is specified periods in a year which have similar weather conditions. Season is a period of the year charcterized by a particular set of weather conditions resulting from the inclination of the earth's axis and the revolution of the earth round the sun. The same cycle of season is repeated year after year.
Climate: The average weather conditions, prevalent from one season to another in the course of a year, over a large area is known as climate.
Factors affecting Climate
Latitude or Distance from the Equator: The places near the equator are warmer than the places which are far away from it.
Altitude or the Height from the mean sea level
Continentally or the Distance from the Sea: The water is a bad conductor of heat i.e. it takes longer time to heat and longer time to cool. Due to this moderating effect of the sea, places near the coast have low range of temperature and high humidity.
Nature of the Prevailing Winds: The on-shore winds bring the moisture from the sea and cause rainfall on the area through which they pass. The off-shore winds coming from the land are dry and help in evaporation.
Cloud Cover: In areas generally of cloudless sky has large diurnal range in temperature. On the other hand under cloudy sky and heavy rainfall areas the range of temperature is very small.
Ocean Currents
Direction of Mountain Chains: The mountain chains act as natural barrier for the wind.
Classification of Climate
Greeks were first to classify the world climates on the basis of the distribution of temperature and insolation.
Torrid Zone
It is situated between the Tropic of Cancer (23½°N) and Tropic of Capricorn (23½°S). The sun's rays are almost vertical throughout the year in this zone.
The mid-day sun is overhead at equator on equinoxes, i.e. on 21st March and 23rd September. It is also overhead at Tropic of Cancer on 21st June and at Tropic of Capricorn on 22nd December.
Temperate Zone
The North Temperate Zone lies between Tropic of Cancer (23½°N) and Arctic Circle (66½°N). The South Temperate Zone lies between Tropic of Capricorn (23½°S) and Antarctic Circle (66½°S).
The difference between the duration of the day and night increases towards the poles.
Frigid Zones
The North Frigid Zone lies between Arctic Circle (66½°N) and North Pole (90°N). The South Frigid Zone lies between Antarctic Circle (66½°S) and South Pole (90°S).
During winter season, the sun does not rise above the horizon for almost six months.