Climate is an important element of the physi­cal environment of mankind, for, although man usually thinks of himself as a creature of the land, he actually lives at the bottom of a deep ‘ocean of air that surrounds the earth’. Climate is the aggregate of atmospheric conditions involving heat, moisture and air movement.

The process of exchange of energy and mass between the earth and the atmosphere over a long period of time result in conditions which we call climate (Richfield, 1979, p. 3). In a developing country like India climatic characteristics have a dominant role in affecting the economic pattern, way of life, mode of living, food preferences, cos­tumes and even the behavioral responses of the people. In India despite a lot of scientific and techno­logical developments our dependence on monsoon rainfall for carrying out successful agricultural ac­tivities, has not been minimised. Similarly vegetari­anism, loose costumes with head gear, courtyard with wide verandahs in houses, festivals and rituals all have been adjusted to the climatic and weather conditions.

The climate of India belongs to the ‘tropical monsoon type’ indicating the impact of its location in tropical belt and the monsoon winds. Although a sizeable part of the country lying north of the Tropic of Cancer falls in the northern temperate zone but the shutting effects of the Himalayas and the existence of the Indian Ocean in the south have played signifi­cant role in giving India a distinctive climatic char­acteristic.

Following are the salient features of the In­dian climate:

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Reversal of Winds

The Indian climate is characterised by the complete reversal of wind system with the change of season in a year. During the winter season winds generally blow from north-east to south-west (land to sea) in the direction of trade winds. These winds are dry, devoid of moisture and are characterised by low temperature and high pressure conditions over the country. During summer season complete re­versal in the direction of the winds is observed and these blow primarily from south-west to north-east (sea to land). During this season the temperature sometimes shoots up to 50° C at some places gener­ating low pressure conditions. The last part of the summer is characterised with high percentage of relative humidity and universal rainfall.

Formation of Alternatively High and Low Pressure Areas over the Land

As in case of wind system there is change in the atmospheric pressure conditions with the change of season. During winter season due to low tempera­ture conditions high pressure area is formed over the northern part (Kashmir and the Punjab) of the coun­try. On the other hand the intense heating of the land during summer season leads to the formation of a thermally induced low pressure cell over the north­western part of the country. These pressure areas with opposite pressure conditions over the neigh­bouring ocean control the direction, intensity and flow of resultant wind systems in respective seasons. That is why winds are generally dry and offshore during winter and moist and onshore during summer season.

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Seasonal and Variable Rainfall

The third characteristic of the Indian climate is related to the seasonality and variability of rain­fall. In India over 80 per cent of annual rainfall is obtained in the latter part of the summer (called rainy season) whose duration ranges from one to 5 months in different parts of the country. Since the rainfall is in the form of heavy downpour it creates problems of floods and soil erosion. There is also variability in rainfall so far time and place are concerned. A place which receives a definite amount of rainfall in a particular year is not sure to get same amount of rainfall in the years to come. Sometimes there is continuous rain for many days and sometimes there is a long spell of dry period. ‘In a quinquennium only one year gets the mean normal amount. Out of the rest four, two receive lesser and the other two higher amounts’ (Singh, J., 1994, p. 61). Similarly there is considerable spatial variation in the general distri­bution of rainfall. ‘Cherrapunji receives 1080 cm over the year, while the annual rainfall at Jaisalmer rarely exceeds 12 cm. Tura, in the Garo Hills, may get in a single day an amount equal to 10 years of rainfall at Jaisalmer (Raza and Ahmed, 1990, p. 36).

Plurality of Seasons

The Indian climate is characterised by con­stantly changing weather conditions. Although there are three main seasons (winter, summer and rainy) but on broader consideration their number goes to six in a year (winter, fall of winter, spring, summer, rainy and autumn). Amongst these spring and a turn are called ‘weaker season’ and their duration may be reduced from 3 to 6 weeks depending up the intensity of the approaching or the receding seasons. This plurality of season denotes the quickly, changing nature of the Indian weather condition which is highly variable. So much so that weather condition of every succeeding day is some who different from the preceding day.

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Characterised by Natural Calamities

Due to its peculiar weather condition especially rainfall the Indian climate is characterised natural calamities like floods, droughts, famines and even epidemics. Continuous heavy down pour may cause devastating floods while the failure of ray leads to severe drought conditions. Although under planned development intensity of these natural ca­lamities affect the life and destiny of the commix people.

In fact Indian climate is so varied and com plea that it denotes climatic extremes and climatic varieties. While it provides enough heat to grow crops and carry on agricultural activities all over the country it also helps in the cultivation of a number of crops belonging to tropical, temperate as well as frigid areas. We have three different cropping sea­sons (Rabi, Kharif and Zaid) and hundreds of varieties of crops.