- India has ‘Tropical Monsoon’ type of climate. The word monsoon has been derived from the Arabic word ‘Mausim’ which means seasonal reversal of the winds during the course of the year.
- The whole of India has a tropical monsoonal climate, since the greater part of the country lies within the trophies, and the climate is influenced by the monsoons.
- The position of the mountain ranges and direction of the rain-bearing winds are the two main factors that determine the climate of India.
- The climate in Indian is strongly influenced by the Himalayas and the Thar Desert.
- During the winter season, the winds generally blow from northeast to southwest (land to sea), while in summer season the winds blow from southwest to northeast (sea to land).
- The average annual rainfall is less than 13 cm over the western Rajasthan, while at Mawsynram in the Meghalaya has as much as 1141 cm. It is the wettest place on the earth.
Seasons in India
|Vasanta||Spring||~ March to May|
|Grishma||Summer||~ May to July|
|Varsha||Monsoon||~ July to September|
|Sharad||Autumn||~ September to November|
|Hemanta||Fall winter||~ November to January|
|Shishira||Winter||~ January to March|
Factors Affecting the Climate of India
India lies between 8° 4′ N and 37° 6′ N latitudes. The Tropic of Cancer passes through the middle of India, thus making the southern half of India in the Torrid Zone and the northern half in the Temperature Zone.
The Himalayas play an important role in lending a sub-tropical touch to the climate of India. The lofty Himalaya Mountains form a barrier which effects the climate of India. It prevents the cold winds of north Asia from blowing into India, thus protecting it from severely cold winters. It also traps the Monsoon winds, forcing them to shed their moisture within the sub-continent.
Temperature decreases with height. Places in the mountains are cooler than places on the plains.
Distance from the sea
With a long coastline, large coastal areas have an equable climate. Areas in the interior of India are far away from the moderating influence of the sea. Such areas have extremes of climate.
Western Disturbances: The low pressure systems that originate over the eastern Mediterranean region in winter and move eastwards towards India passing over Iran, Afghanistan and Pakistan are responsible for the winter rain in northern India.
Conditions in the Regions Surrounding India: Temperature and pressure conditions in East Africa, Iran, Central Asia and Tibet determine the strength of the monsoons and the occasional dry spells. For example, high temperatures in East Africa may draw the monsoon winds from the Indian Ocean into that region thus, causing a dry spell.
Conditions over the Ocean: The weather conditions over the Indian Ocean and the China Sea may be responsible for typhoons which often affect the east coast of India.
Jet Streams: Air currents in the upper layers of the atmosphere known as jet steams could determine the arrival of the monsoons and departure of the monsoons. The Scientists are studying the jet streams and how it may affect the climate of India but much remains to be learned about this phenomena.
Climatic Regions of India
Tropical Rain Forest
- This type of climate is found on the west coastal plain and Sahyadris and in parts of Assam.
- The temperatures are high, not falling below 18.2 ° c even during winter and rising to 29 ° C in April and May, the hottest months.
- Most of the peninsula, except the semiarid zone in the leeside of the Sahyadris experiences this type of climate.
- A long dry weather lasting through winter and early summer and high temperature remaining above 18.2 ° C even during the winter seasons and rising as high as 32 ° C in summer are the chief characteristics of this climate.
- Nagpur has a mean temperature of 35.4 ° C for May which is the hottest month and 20.7 ° C for December the coldest month in the year.
- The natural vegetation all over the area is savanna.
Tropical Semi-Arid Steppe Climate
- The rain-shadow belt, running southward from central Maharashtra to Tamil Nadu, in the leeside of the Sahyadris and Cardamom Hills come under this type of climate of low and uncertain rainfall.
- Temperature varying from 20 ° C to 23.8 ° C for December and 32.8 ° C for May. Agriculturally, the climate is suitable only for dry farming and livestock rearing.
Tropical and Sub-Tropical Steppe
- This type of climate occurs over a broad crescent from Punjab to Kachchh between the Thar Desert to its west and the more humid climates of the Ganga Plain and the Peninsula to its east and south respectively.
- The climate, therefore, is transitional between these two areas. The annual rainfall is not only low but it is also highly erratic.
- The western part of Barmer, Jaisalmer and Bikaner districts of Rajasthan and most of the part of Kachchh form the sandy wastes of the Thar which experiences a typical desert climate.
- Ganganagar has recorded a maximum temperature of 50 ° C, the highest record.
Humid Sub-Tropical with Winter
- A large area to the south of the Himalayas, east of the tropical and sub-tropical steppe and north of the tropical savanna running in a long belt from Punjab to Assam with a south-westward extension into Rajasthan east of the Aravalli Range, has this type of climate.
- Winers are dry except for a little rain received from the westerly depressions.
- The Himalayan and Karakoram ranges experience this type of climate with sharp contrasts between the temperatures of the sunny and shady slopes, high diurnal range of temperatures and high variability of rainfall.
- The trans-Himalayan region, Ladakh, where the south-west monsoon fails to reach, has a dry and cold climate and a spare and stunned vegetation.
Drought in India
- The dry areas of Rajasthan and the adjoining part of Haryana and Gujarat are liable to frequent drought conditions.
- Another area liable to frequent drought lies on the leeward side of the Western Ghats.
Characteristics of Rainfall in India
Type of Rainfall
|Areas of very little rainfall (lower than 50 cm)||Western Rajasthan, northern part of Kashmir, the Deccan Plateau and Punjab.|
|Areas of low precipitation
|Eastern Rajasthan, Upper Ganga basin, Southern plains of Karnataka, Punjab, Tamil Nadu, and Andhra Pradesh.|
|Areas of comparatively heavy rainfall (100-200 cm)||Southern areas of Gujarat, north-eastern Peninsular region, east Tamil Nadu, eastern Maharashtra, Western Ghats, Orissa, Madhya Pradesh, and the central Gangetic basin.|
|Areas of heavy rainfall
(more than 200 cm)
|The western seashores, the Western Ghats, Hills of Meghalaya, and the Sub-Himalayan range territories in North East. West Bengal, Assam, Western Coast, and southern part of east Himalayas.|