climatic zones in india

ZONES

1. Different climatic zones in India

2. Tropical wet humid climate The regions belonging to this group experience persistent high temperatures which normally do not go below 18°C even in the coolest month. Tropical wet (humid) or monsoon type climate The west coastal lowlands, the Western Ghats, and southern parts of Assam have this climate type.

3. It is characterize by high temperatures throughout the year, even in the hills. The rainfall here is seasonal, but heavy and is above 78 cm in a year. Most of the rain is received in the period from May to November, and is adequate for the growth of vegetation during the entire year.

4. December to March are the dry months with very little rainfall. The heavy rain is responsible for the tropical wet forests in these regions, which consists of a large number of species of animals. Evergreen forests are the typical feature of the region.

5. Tropical wet and dry or savannah climate Most of the plateau of peninsular India enjoys this climate, except a semi-arid tract to the east of the Western Ghats . Winter and early summer are long dry periods with temperature above 18°C. Summer is very hot and the temperatures in the interior low level areas can go above 45°C during May.

6. Only central eastern Tamil Nadu falls under this tract and receives rainfall during the winter months of late November to January The rainy season is from June to September and the annual rainfall is between 75 and 150 cm.

7. Dry climate group This group consists of regions where the rate of evaporation of water is higher than the rate of moisture received through precipitation .

8. A long stretch of land situated to the south of Tropic of Cancer and east of the western Ghats and the Cardamom Hills experiences this climate. It includes Karnataka, interior and western Tamil Nadu, western  Andhra Pradesh and central Maharashtra. Tropical semi-arid (steppe) climate

9. This area receives minimal rainfall due to being situated in the rain shadow area. This region is a famine prone zone with very unreliable rainfall which varies between 40 to 75 cm annually. Towards the north of Krishna River the summer monsoon is responsible for most of the rainfall, while to the south of the river rainfall also occurs in the months of October and November .

10. The coldest month is December but even in this month the temperature remains between 20°C and 24°C. The months of March to May are hot and dry with mean monthly temperatures of around 32°C.

11. The vegetation mostly comprises grasses with a few scattered trees due to the rainfall. Hence this area is not very well suited for permanent agriculture.

12. Most of western Rajasthan falls under this climate type characterized by scanty rainfall. Cloud bursts are largely responsible for the all the rainfall seen in this region which is less than 30 cm. Sub-tropical arid (desert) climate These happen when the monsoon winds penetrate this region in the months of July, August and September.

13. The rainfall is very erratic and a few regions might not see rainfall for a couple of years. The summer months of May and June are very hot with mean monthly temperatures in the region of 35°C and highs which can sometimes reach 50°C. During winters the temperatures can drop below freezing in some areas due to cold wave.

14. There is a large diurnal range of about 14°C during summer which becomes higher by a few more degrees during winter. This extreme climate makes this a sparsely populated region of India. The region towards the east of the tropical desert running from Punjab and Haryana to Kathiawar experiences this climate type.

15. Sub-tropical semi-arid (steppe) climate   This climate is a transitional climate falling between tropical desert and humid sub-tropical, with temperatures which are less extreme than the desert climate. The annual rainfall is between 30 to 65 cm but is very unreliable and happens mostly during the summer monsoon season. Maximum temperatures during summer can rise to 40°C.

16. The vegetation mostly comprises short coarse grass. Some crops like  jowar  and  bajra  are also cultivated.

17. Sub-tropical humid climate group The temperature during the coldest months in regions experiencing this climate falls between 18 and 0°C. Sub-tropical humid (wet) with dry winters The foothills of the Himalayas, Punjab-Haryana plain adjacent to the Himalayas, Rajasthan east of the Aravalli range, Uttar Pradesh, Bihar and northern part of West Bengal and Assam experience this climate.

18. The rainfall is received mostly in the summer and is about 65 cm in the west and increases to 250 cm annually to the east and near the Himalayas. The winters are mainly dry due to the land derived winter winds which blow down the lowlands of north India towards the Bay of Bengal.

19. The summers are hot and temperatures can reach 46°C in the lowlands. May and June are the hottest months. Winter months are mostly dry with feeble winds. Frost occurs for a few weeks in winter. The difference in rainfall between the east and the west gives rise to a wide difference in the natural vegetation.

20. Mountain climate or highland climate or alpine climate In the Himalayan mountains the temperature falls by 0.6°C for every 100  m rise in altitude and this gives rise to a variety of climates from nearly tropical in the foothills to tundra type above the snow line. One can also observe sharp contrast between temperatures of the sunny and shady slopes, high diurnal range of temperature, inversion of temperature, and variability of rainfall based on altitude.

21. The northern side of the western Himalayas also known as the trans-Himalayan belt is arid, cold and generally wind swept. The vegetation is sparse and stunted as rainfall is scanty and the winters are severely cold. Most of the snowfall is in the form of snow during late winter and spring months.

22. The area to the south of the Himalayan range is protected from cold winds coming from interior of Asia during winter. The leeward side of the mountains receive less rain while the well exposed slopes get heavy rainfall. The places situated between 1070 and 2290 m altitudes receive the heaviest rainfall and the rainfall decreases rapidly above 2290m.

23. The great Himalayan range witnesses heavy snowfall during winter months of December to February at altitudes above 1500m. The diurnal range of temperature is also high. The states of Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Arunachal Pradesh, and Sikkim experience this kind of weather.

24. The design criteria should therefore aim at resisting heat gain by providing shading, reducing exposed area, controlling and scheduling ventilation, and increasing thermal capacity. The presence of “water bodies” is desirable as they can help increase the humidity, thereby leading to lower air temperatures. Design criteria

25. The ground and surrounding objects emit a lot of heat in the afternoons and evenings. As far as possible, this heat should be avoided by appropriate design features.

26.  Massive structure  Air locks, lobbies, balconies, and verandahs  Weather stripping and scheduling air changes External surfaces protected by overhangs, fins, and trees  Pale colors and glazed china mosaic tiles  Cooling Windows and exhausts. Some of the design features for buildings in this climate are:  Appropriate orientation and shape of building  Insulation of building envelope

27. China mosaic tiles

28. Courtyards, wind towers, and arrangement of openings. Wind tower

29. The warm and humid zone covers the coastal parts of the country, such as Mumbai, Chennai and Kolkata . The main design criteria in the warm and humid region are to reduce heat gain by providing shading, and promote heat loss by maximizing cross ventilation. Dissipation of humidity is also essential to reduce discomfort. Warm and humid

30. Some of the design features for buildings in this climate are:  Appropriate orientation and shape of building Roof insulation and wall insulation  Reflective surface of roof  Balconies and verandahs Walls glass surface protected by overhangs, fins, and trees. Pale colors and glazed china mosaic tiles  Windows and exhausts Ventilated roof construction, courtyards, wind towers, and arrangement of openings  Dehumidifiers and desiccant cooling

31. Moderate Pune and Bangalore are examples of cities that fall under this climatic zone. The design criteria in the moderate zone are to reduce heat gain by providing shading, and to promote heat loss by ventilation. Some of the design features for buildings in this climate are:  Appropriate orientation and shape of building  Roof insulation and east and west wall insulation

32. Walls facing east and west, glass surface protected by overhangs, fins , and trees. Pale colors and glazed china mosaic tiles Windows and exhausts  Courtyards and arrangement of openings

33. Cold Generally, the northern part of India experiences this type of climate. The design criteria are to resist heat loss by insulation and controlling infiltration. Simultaneously, heat gain needs to be promoted by admitting and trapping solar radiation within the living space.

34. Some of the design features for buildings in this climate are:  Appropriate orientation and shape of building  Use of trees as wind barriers  Roof insulation, wall insulation, and double glazing  Thicker walls  Air locks and lobbies  Weather stripping  Darker colours  Sun spaces, greenhouses and thrombi walls

35. Dark colors for building Double glazing Weather stripping

36. Composite The composite zone covers the central part of India, such as New Delhi, Kanpur and Allahabad. The design criteria are more or less the same as for hot and dry climate except that maximizing cross ventilation is desirable in the monsoon period . Some of the design features for buildings in this climate are:  Appropriate orientation and shape of building  Use of trees as wind barriers

37.  Walls, glass surfaces protected by overhangs, fins, and trees  Pale colours and glazed china mosaic tiles  Exhausts  Courtyards, wind towers, and arrangement of openings  Trees and ponds for evaporative cooling  Dehumidifiers and desiccant cooling  Roof insulation and wall insulation  Thicker walls  Air locks and balconies  Weather stripping

38. dehumidifiers

39. Exhaust ventilation