{"id":603,"date":"2021-02-13T10:35:02","date_gmt":"2021-02-13T05:05:02","guid":{"rendered":"http:\/\/knowledgekart.in\/blog\/?p=603"},"modified":"2022-02-14T12:15:11","modified_gmt":"2022-02-14T06:45:11","slug":"climate-of-india-for-upsc-ias-2022-a-topic-of-indian-geography-g-k","status":"publish","type":"post","link":"https:\/\/knowledgekart.in\/blog\/climate-of-india-for-upsc-ias-2022-a-topic-of-indian-geography-g-k\/","title":{"rendered":"Climate of India For UPSC IAS 2022.A Topic of Indian Geography & G.K"},"content":{"rendered":"

Climate of India For UPSC IAS 2022.A Topic of Indian Geography & G.K<\/h2>\n

\"Climate<\/a><\/p>\n

The Climate of India<\/b><\/i> comprises a wide range of weather conditions across a vast geographic scale and varied topography, making generalisations difficult. Based on the K\u00f6ppen system<\/a>, India<\/a> hosts six major climatic subtypes, ranging from arid desert in the west, alpine tundra and glaciers in the north, and humid tropical regions supporting rainforests in the southwest and the island territories. Many regions have starkly different microclimates<\/a>. The country’s meteorological department follows the international standard of four climatological seasons with some local adjustments: winter (December, January and February), summer (March, April and May), a monsoon rainy<\/a> season (June to September), and a post-monsoon period (October to November). Climate of India For UPSC IAS 2020.A Topic of Indian Geography & G.K<\/p>\n

India’s geography<\/a> and geology<\/a> are climatically pivotal: the Thar Desert<\/a> in the northwest and the Himalayas<\/a> in the north work in tandem to effect a culturally<\/a> and economically<\/a> important monsoonal regime. As Earth’s highest and most massive mountain range, the Himalayas<\/a> bar the influx of frigid katabatic winds<\/a> from the icy Tibetan Plateau<\/a> and northerly Central Asia. Most of North India<\/a> is thus kept warm or is only mildly chilly or cold during winter; the same thermal dam keeps most regions in India hot in summer.<\/p>\n

Though the Tropic of Cancer<\/a>\u2014the boundary between the tropics and subtropics\u2014passes through the middle of India, the bulk of the country can be regarded as climatically tropical. As in much of the tropics, monsoonal and other weather patterns in India can be wildly unstable: epochal droughts, floods, cyclones, and other natural disasters are sporadic, but have displaced or ended millions of human lives. There is one scientific opinion which states that in South Asia such climatic events are likely to change in unpredictability, frequency, and severity<\/a>. Ongoing and future vegetative changes and current sea level rises<\/a> and the attendant inundation of India’s low-lying coastal areas are other impacts, current or predicted, that are attributable to global warming<\/a>.<\/sup><\/p>\n

History- Climate of India
\n<\/span><\/h2>\n
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During the Triassic<\/a> period of some 251\u2013199.6\u00a0Ma<\/a>, the Indian subcontinent was part of a vast supercontinent<\/a> known as Pangaea<\/a>. Despite its position within a high-latitude belt at 55\u201375\u00b0\u00a0S\u2014latitudes now occupied by parts of the Antarctic Peninsula<\/a>, as opposed to India’s current position between 5 and 35\u00b0\u00a0N\u2014India likely experienced a humid temperate climate with warm and frost-free weather, though with well-defined seasons.India later merged into the southern supercontinent Gondwana<\/a>, a process beginning some 550\u2013500\u00a0Ma. During the Late Paleozoic<\/a>, Gondwana extended from a point at or near the South Pole<\/a> to near the equator, where the Indian craton<\/a> (stable continental crust<\/a>) was positioned, resulting in a mild climate favourable to hosting high-biomass<\/a> ecosystems<\/a>. This is underscored by India’s vast coal reserves\u2014much of it from the late Paleozoic sedimentary sequence\u2014the fourth-largest reserves in the world. During the Mesozoic<\/a>, the world, including India, was considerably warmer than today. With the coming of the Carboniferous<\/a>, global cooling<\/a> stoked extensive glaciation<\/a>, which spread northwards from South Africa towards India; this cool period lasted well into the Permian<\/a>.<\/div>\n<\/div>\n

Tectonic movement<\/a> by the Indian Plate<\/a> caused it to pass over a geologic hotspot<\/a>\u2014the R\u00e9union hotspot<\/a>\u2014now occupied by the volcanic island of R\u00e9union<\/a>. This resulted in a massive flood basalt<\/a> event that laid down the Deccan Traps<\/a> some 60\u201368\u00a0Ma, at the end of the Cretaceous<\/a> period. This may have contributed to the global Cretaceous\u2013Paleogene extinction event<\/a>, which caused India to experience significantly reduced insolation<\/a>. Elevated atmospheric levels of sulphur gases formed aerosols<\/a> such as sulphur dioxide<\/a> and sulphuric acid<\/a>, similar to those found in the atmosphere of Venus<\/a>; these precipitated as acid rain<\/a>. Elevated carbon dioxide<\/a> emissions also contributed to the greenhouse effect<\/a>, causing warmer weather<\/a> that lasted long after the atmospheric shroud of dust and aerosols had cleared. Further climatic changes 20 million years ago, long after India had crashed into the Laurasian<\/a> landmass, were severe enough to cause the extinction of many endemic Indian forms. The formation of the Himalayas resulted in blockage of frigid Central Asian air, preventing it from reaching India; this made its climate significantly warmer and more tropical in character than it would otherwise have been<\/sup><\/p>\n

Regions- Climate of India
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Main article: Climatic regions of India<\/a><\/div>\n\n\n\n
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\""India<\/a><\/p>\n
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<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n
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Average annual temperatures across India:<\/p>\n\n\n\n\n\n\n\n
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\u00a0<\/span>\u00a0< 20.0\u00a0\u00b0C<\/div>\n<\/td>\n
(< 68.0\u00a0\u00b0F)<\/td>\n<\/tr>\n
\n
\u00a0<\/span>\u00a020.0\u201322.5\u00a0\u00b0C<\/div>\n<\/td>\n
(68.0\u201372.5\u00a0\u00b0F)<\/td>\n<\/tr>\n
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\u00a0<\/span>\u00a022.5\u201325.0\u00a0\u00b0C<\/div>\n<\/td>\n
(72.5\u201377.0\u00a0\u00b0F)<\/td>\n<\/tr>\n
\n
\u00a0<\/span>\u00a025.0\u201327.5\u00a0\u00b0C<\/div>\n<\/td>\n
(77.0\u201381.5\u00a0\u00b0F)<\/td>\n<\/tr>\n
\n
\u00a0<\/span>\u00a0> 27.5\u00a0\u00b0C<\/div>\n<\/td>\n
(> 81.5\u00a0\u00b0F)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/td>\n\n
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\""India<\/a><\/p>\n
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<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n
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Climatic zones in India, based on the K\u00f6ppen classification system<\/a>:<\/p>\n\n\n\n\n\n\n\n\n
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\u00a0<\/span>\u00a0Alpine<\/a><\/div>\n<\/td>\n
E<\/b><\/td>\n(ETh)<\/i><\/td>\n<\/tr>\n
\n
\u00a0<\/span>\u00a0Humid subtropical<\/a><\/div>\n<\/td>\n
C<\/b><\/td>\n(Cwa)<\/i><\/td>\n<\/tr>\n
\n
\u00a0<\/span>\u00a0Tropical wet-dry<\/a><\/div>\n<\/td>\n
A<\/b><\/td>\n(Aw)<\/i><\/td>\n<\/tr>\n
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\u00a0<\/span>\u00a0Tropical wet<\/a><\/div>\n<\/td>\n
A<\/b><\/td>\n(Am)<\/i><\/td>\n<\/tr>\n
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\u00a0<\/span>\u00a0Semi-arid<\/a><\/div>\n<\/td>\n
B<\/b><\/td>\n(BSh)<\/i><\/td>\n<\/tr>\n
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\u00a0<\/span>\u00a0Arid<\/a><\/div>\n<\/td>\n
B<\/b><\/td>\n(BWh)<\/i><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

India is home to an extraordinary variety of climatic regions, ranging from tropical in the south to temperate and alpine in the Himalayan north, where elevated regions receive sustained winter snowfall. The nation’s climate is strongly influenced by the Himalayas and the Thar Desert. The Himalayas, along with the Hindu Kush<\/a> mountains in Pakistan, prevent cold Central Asian katabatic winds from blowing in, keeping the bulk of the Indian subcontinent warmer than most locations at the similar latitudes<\/a>. Simultaneously, the Thar Desert plays a role in attracting moisture-laden southwest summer monsoon winds that, between June and October, provide the majority of India’s rainfall. Four major climatic groupings predominate, into which fall seven climatic zones that, as designated by experts, are defined on the basis of such traits as temperature and precipitation. Groupings are assigned codes (see chart) according to the K\u00f6ppen climate classification system.<\/p>\n

Tropical wet- Climate of India
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A tropical rainy climate governs regions persistent to warm or high temperatures, which normally do not fall below 18\u00a0\u00b0C (64\u00a0\u00b0F). India hosts two climatic subtypes- tropical monsoon climate<\/a>, tropical wet and dry climate<\/a> that fall under this group.<\/p>\n

1) The most humid is the tropical wet climate\u2014also known as a tropical monsoon climate<\/a>\u2014that covers a strip of southwestern lowlands abutting the Malabar Coast<\/a>, the Western Ghats<\/a>, and southern Assam. India’s two island territories, Lakshadweep and the Andaman and Nicobar Islands, are also subject to this climate. Characterised by moderate to high year-round temperatures, even in the foothills, its rainfall is seasonal but heavy\u2014typically above 2,000\u00a0mm (79\u00a0in) per year. Most rainfall occurs between May and November; this moisture is enough to sustain lush forests and other vegetation for the rest of the mainly dry year. December to March are the driest months, when days with precipitation are rare. The heavy monsoon rains are responsible for the exceptional biodiversity of tropical wet forests in parts of these regions.<\/p>\n

2) In India a tropical wet and dry climate<\/a> is more common. Noticeably drier than areas with a tropical monsoon climate, it prevails over most of inland peninsular India except for a semi arid rain shadow<\/a> east of the Western Ghats. Winter and early summer are long and dry periods with temperatures averaging above 18\u00a0\u00b0C (64\u00a0\u00b0F). Summer is exceedingly hot; temperatures in low-lying areas may exceed 50\u00a0\u00b0C (122\u00a0\u00b0F) during May, leading to heat waves that can each kill hundreds of Indians. The rainy season lasts from June to September; annual rainfall averages between 750\u20131,500\u00a0mm (30\u201359\u00a0in) across the region. Once the dry northeast monsoon begins in September, most precipitation in India falls on Tamil Nadu, leaving other states comparatively dry.<\/p>\n

The Ganges Delta lies mostly in the tropical wet climate zone: it receives between 1,500 to 2,000\u00a0mm (59 to 79\u00a0in) of rainfall each year in the western part, and 2,000 to 3,000\u00a0mm (79 to 118\u00a0in) in the eastern part. The coolest month of the year, on average, is January; April and May are the warmest months. Average temperatures in January range from 14 to 25\u00a0\u00b0C (57 to 77\u00a0\u00b0F), and average temperatures in April range from 25 to 35\u00a0\u00b0C (77 to 95\u00a0\u00b0F). July is on average the coldest and wettest month: over 330\u00a0mm (13\u00a0in) of rain falls on the delta<\/sup><\/p>\n

Tropical dry<\/span><\/h3>\n

A tropical arid<\/a> and semi-arid<\/a> climate dominates regions where the rate of moisture loss through evapotranspiration<\/a> exceeds that from precipitation; it is subdivided into three climatic subtypes- tropical semi-arid steppe, arid climate, tropical and sub-tropical steppe climate.<\/p>\n

1) The first, a tropical semi-arid steppe climate<\/b>, (Hot semi-arid climate<\/a>) predominates over a long stretch of land south of Tropic of Cancer and east of the Western Ghats and the Cardamom Hills<\/a>. The region, which includes Karnataka, inland Tamil Nadu, western Andhra Pradesh, and central Maharashtra, gets between 400\u2013750 millimetres (15.7\u201329.5\u00a0in) annually. It is drought-prone, as it tends to have less reliable rainfall due to sporadic lateness or failure of the southwest monsoon. Karnataka is divided into three zones \u2013 coastal, north interior and south interior. Of these, the coastal zone receives the heaviest rainfall with an average rainfall of about 3,638.5\u00a0mm per annum, far in excess of the state average of 1,139\u00a0mm (45\u00a0in). In contrast to norm, Agumbe in the Shivamogga district receives the second highest annual rainfall in India. North of the Krishna River<\/a>, the summer monsoon is responsible for most rainfall; to the south, significant post-monsoon rainfall also occurs in October and November. In December, the coldest month, temperatures still average around 20\u201324\u00a0\u00b0C (68\u201375\u00a0\u00b0F). The months between March to May are hot and dry; mean monthly temperatures hover around 32\u00a0\u00b0C, with 320 millimetres (13\u00a0in)precipitation. Hence, without artificial irrigation, this region is not suitable for permanent agriculture.<\/p>\n

2) Most of western Rajasthan experiences an arid climatic regime<\/b> (Hot desert climate<\/a>). Cloudbursts<\/a> are responsible for virtually all of the region’s annual precipitation, which totals less than 300 millimetres (11.8\u00a0in). Such bursts happen when monsoon winds sweep into the region during July, August, and September. Such rainfall is highly erratic; regions experiencing rainfall one year may not see precipitation for the next couple of years or so. Atmospheric moisture is largely prevented from precipitating due to continuous downdrafts<\/a> and other factors.[20]<\/a><\/sup> The summer months of May and June are exceptionally hot; mean monthly temperatures in the region hover around 35\u00a0\u00b0C (95\u00a0\u00b0F), with daily maxima occasionally topping 50\u00a0\u00b0C (122\u00a0\u00b0F). During winters, temperatures in some areas can drop below freezing due to waves of cold air from Central Asia. There is a large diurnal range of about 14\u00a0\u00b0C (25.2\u00a0\u00b0F) during summer; this widens by several degrees during winter.<\/p>\n

To the west, in Gujarat, diverse climate conditions obtain. The winters are mild, pleasant, and dry with average daytime temperatures around 29\u00a0\u00b0C (84\u00a0\u00b0F) and nights around 12\u00a0\u00b0C (54\u00a0\u00b0F) with virtually full sun and clear nights. Summers are hot and dry with daytime temperatures around 41\u00a0\u00b0C (106\u00a0\u00b0F) and nights no lower than 29\u00a0\u00b0C (84\u00a0\u00b0F). In the weeks before the monsoon temperatures are similar to the above, but high humidity makes the air more uncomfortable. Relief comes with the monsoon. Temperatures are around 35\u00a0\u00b0C (95\u00a0\u00b0F) but humidity is very high; nights are around 27\u00a0\u00b0C (81\u00a0\u00b0F). Most of the rainfall occurs in this season, and the rain can cause severe floods. The sun is often occluded during the monsoon season.<\/p>\n

3) East of the Thar Desert, the Punjab-Haryana-Kathiawar region experiences a tropical and sub-tropical steppe climate<\/b>. Haryana’s climate resembles other states of the northern plains: extreme summer heat of up to 50\u00a0\u00b0C and winter cold as low as 1\u00a0\u00b0C. May and June are hottest; December and January are coldest. Rainfall is varied, with the Shivalik Hills region being the wettest and the Aravali Hills region being the driest. About 80% of the rainfall occurs in the monsoon season of July\u2013September, which can cause flooding. The Punjabi climate is also governed by extremes of hot and cold. Areas near the Himalayan foothills receive heavy rainfall whereas those eloigned from them are hot and dry. Punjab’s three-season climate sees summer months that span from mid-April to the end of June. Temperatures typically range from\u20132\u00a0\u00b0C to 40\u00a0\u00b0C, but can reach 47\u00a0\u00b0C (117\u00a0\u00b0F) in summer and \u22124\u00a0\u00b0C in winter. In this zone, a transitional climatic region separating tropical desert from humid sub-tropical savanna and forests, experiences temperatures that are less extreme than those of the desert. Average annual rainfall is 300\u2013650 millimetres (11.8\u201325.6\u00a0in), but is very unreliable; as in much of the rest of India, the southwest monsoon accounts for most precipitation. Daily summer temperature maxima rise to around 40\u00a0\u00b0C (104\u00a0\u00b0F); this results in natural vegetation typically comprising short, coarse grasses.<\/p>\n

Subtropical humid<\/span><\/h3>\n

Most of Northeast India and much of North India are subject to a humid subtropical climate<\/a>. Though they experience hot summers, temperatures during the coldest months may fall as low as 0\u00a0\u00b0C (32\u00a0\u00b0F). Due to ample monsoon rains, India has only one subtype of this climate under the K\u00f6ppen system: Cwa<\/i>.<\/a><\/sup> In most of this region, there is very little precipitation during the winter, owing to powerful anticyclonic and katabatic (downward-flowing) winds from Central Asia.<\/p>\n

Humid subtropical regions are subject to pronounced dry winters. Winter rainfall\u2014and occasionally snowfall\u2014is associated with large storm systems such as “Nor’westers” and “Western disturbances<\/a>“; the latter are steered by westerlies<\/a> towards the Himalayas. Most summer rainfall occurs during powerful thunderstorms associated with the southwest summer monsoon; occasional tropical cyclones<\/a> also contribute. Annual rainfall ranges from less than 1,000 millimetres (39\u00a0in) in the west to over 2,500 millimetres (98\u00a0in) in parts of the northeast. As most of this region is far from the ocean, the wide temperature swings more characteristic of a continental climate<\/a> predominate; the swings are wider than in those in tropical wet regions, ranging from 24\u00a0\u00b0C (75\u00a0\u00b0F) in north-central India to 27\u00a0\u00b0C (81\u00a0\u00b0F) in the east.<\/p>\n

Mountain<\/span><\/h3>\n

India’s northernmost areas are subject to a montane, or alpine, climate. In the Himalayas, the rate at which an air mass’s temperature falls per kilometre (3,281\u00a0ft) of altitude gained (the dry adiabatic lapse rate<\/a>) is 9.8\u00a0\u00b0C\/km. In terms of environmental lapse rate<\/a>, ambient temperatures fall by 6.5\u00a0\u00b0C (11.7\u00a0\u00b0F) for every 1,000 metres (3,281\u00a0ft) rise in altitude. Thus, climates ranging from nearly tropical in the foothills to tundra above the snow line<\/a> can coexist within several hundred metres of each other. Sharp temperature contrasts between sunny and shady slopes, high diurnal temperature variability, temperature inversions, and altitude-dependent variability in rainfall are also common.<\/p>\n

The northern side of the western Himalayas, also known as the trans-Himalayan belt, has a cold desert climate<\/a>. It is a region of barren, arid, frigid<\/b> and wind-blown wastelands. Areas south of the Himalayas are largely protected from cold winter winds coming in from the Asian interior. The leeward side (northern face) of the mountains receives less rain.<\/p>\n

The southern slopes of the western Himalayas, well-exposed to the monsoon, get heavy rainfall. Areas situated at elevations of 1,070\u20132,290 metres (3,510\u20137,510\u00a0ft) receive the heaviest rainfall, which decreases rapidly at elevations above 2,290 metres (7,513\u00a0ft). Most precipitation occurs as snowfall during the late winter and spring months.The Himalayas experience their heaviest snowfall between December and February and at elevations above 1,500 metres (4,921\u00a0ft). Snowfall increases with elevation by up to several dozen millimetres per 100\u00a0metre (~2\u00a0in; 330\u00a0ft) increase. Elevations above 6,000 metres (19,685\u00a0ft) never experience rain; all precipitation falls as snow.<\/sup><\/p>\n

Seasons<\/span><\/h2>\n

The India Meteorological Department<\/a> (IMD) designates four climatological seasons:<\/sup><\/p>\n