Climate of India

India's climate is largely factored by the Himalayas and the Thar Desert. The Himalayas, along with the Hindu Kush mountains in Pakistan, provide a barrier to the cold winds from Central Asia. This keeps most of the Indian subcontinent warmer than most locations in similar latitudes. It is difficult to generalise India's climate. India's huge size sees climatic conditions in Kashmir having little relation to that in the extreme south. In addition to this, the varied topography of the land sees many regions having their own microclimates.

The Tropic of Cancer passes almost through the middle of India. Hence India lies in both the tropical and the sub-tropical regions. The himalayas ensure that the temperatures in the northern part of India are 5°C warmer than similar latitude regions during winter, by stopping the cold polar winds. This means that north India is warm or midly cool during winter and hot during summer. Hence India is considered as a tropical country.

India has three distinct seasons:

1. Summer - from March to June
2. Rainy - from June to October
3. Winter - from November to March

Contents

1 Summer 2 Monsoons 2.1 Southwest Monsoons 2.2 Northeast Monsoons 3 Winter 4 Withdrawal of Monsoons 5 Autumn and Spring 6 Records 7 Reference

Summer

'Summer season lasts in north western India from April to June and from March to June in the rest of the country. The temperatures in the north rises as the vertical rays of the Sun reaches Tropic of Cancer. The hottest month for the western and southern regions of the peninsular is April, while for the northern regions it is May. By May, most of interior India experiences mean temperatures over 32°C and maximum temperatures of exceeding 40°C. Temeratures as high as 49°C and higher have been recorded in parts of India during this season. In coastal India the temperature hovers around 36°C, but it is extremely humid here owing to the proximity to the sea. In south India the temperatures are higher on the east coast by a few degrees compared to west coast.

Altitude effects the temperture to a large extent, with the higher parts of deccan plateau and hills being relatively cooler. The Himalayan and Nilgiri hill stations offer some respite from the heat with a temperate high of 25°C. North eastern India also has a much milder climate with temperatures rarely exceeding 32°C.

Monsoons

The monsoons come as a relief from the heat and parched landscape. The rains bring down the temperature, and make the surroundings lush and green. It is the best season to go hiking and trekking. The monsoons are intricately linked to the economy as a good monsoon results in a booming economy. The rains fill the ground water tables and reinvigorate rivers and lakes.

Southwest Monsoons

The southwest monsoons supplies over 80% of India's annual rainfall. It consists of two arms, the Bay of Bengal arm, and the Arabian Sea to the low pressure area over the Thar desert in Rajasthan.

The monsoon makes its presence felt by the end of May. It starts around the 29 May, hitting the Andaman and Nicobar Islands in the Bay of Bengal. It strikes the mainland of Kerala on 1 June. By 9 June, it makes hits Mumbai, and Delhi by 29 June. The Bay of Bengal moves in a northwest direction whereas the Arabian Sea arm moves in a north by northeast direction. By first week of July, the entire country experiences rain. Predictably, southern India receives more rainfall than northern India.

During this season, cyclones occur, causing widespread devastation to coastal regions. Cherrapunji, Meghalaya, the world's wettest place, received 2.647 m of rainfall. The monsoons start withdrawing by the last week of August. By mid September, it has withdrawn from Mumbai and by October, the southwest monsoons have completely withdrawn from India.

Northeast Monsoons

After the withdrawal of the monsoons, the northeast monsoons begin by November. Supplying 20% of India rainfall it doesn't cover the entire country but only the states of Tamil Nadu, West Bengal, Arunachal Pradesh, Karnataka and Meghalaya. Cold mountain air travelling along the Brahmaputra river brings rain to the northeast region of India.

Winter

The temperture gradually falls in the country after September. As the vertical rays of the sun move south of the equator, the country experiences cool weather, with temperatures decreasing as we move north. The himalayas do not let the cold and dry winds of the interior of Asia penetrate into India, which leads to a fairly small gradient in temperature of 0.5°C for 1° latitude. December and January are typically the coldest months with mean temperatures of 50 to 60°C in the north-west and the himalayan region. The mean temperatures increase as we move towards east as well as south, where it can be between 70 to 80°C.

In north-western India October and November are cloudless and least dusty months in the year, with feeble winds. This leads to a high diurnal range of temperatures during these months. It ranges betweem 16 to 20°C in north-western India, while it is nearly 5°C less in central India and 10°C less on the coastal strip. Northern India doesn't receive snow, except for the mountains and the temperature in the plains rarely falls below freezing. Highs in Delhi range between 12° to 18°C. Night time temperatures fall to around 2 to 6°C. Further north in Punjab the lows does fall below freezing in the plains to around -6°C in Amritsar. Frost sometimes occurs, but the hallmark of the season is the notorious fog which disrupts daily life.

Northern India does receive some rainfall. The source is from the western disturbances originating in the Mediterranean Sea. These disturbances travel westwards, but unable to climb the Himalaya, they drop their rainfall and snow over northern India. Eastern India has a much milder climate. It has mild days and cool nights. High's range from 17- 21°C. Nights average 9°C. The northeast rainfall brings rain to this region. The cold winds over the Brahmaputra river lower the temperatures.

In south India, the weather is cooler only in the central part of the Indian plateau, the Karnataka plateau and hilly areas. This only lasts for a short period of time. These interior areas can fall to about 16°C. Coastal areas and low-level interior tracts are warm with highs of 30°C and lows of 21°C. The Nilgiri range is the exception where the lows can fall below freezing.

Withdrawal of Monsoons

This is not a true season as such. Many text books however, refer to this as a separate season. This season lasts between September and December depending on its location. The weather turns more dry and the grass starts to dry up. This season marks the transition from wet to dry climate in most parts of India. Highs range between 34°C and 28°C.

Autumn and Spring

Autumn and spring seasons only occur in the Himalayan states of Himachal Pradesh, Kashmir and Sikkim. These regions have a temperate season and experience 5 seasons annually.

Records

The highest temperature recoded in India was 50.6 °C (123.08 °F)in Alwar in 1955. The lowest was −45 °C (−49 °F) in Kashmir. Recent claims of temperatures touching 55 °CTemplate:Ref (131 °F) in Orissa have been met with some scepticism by the Met department, largely on the method of recording of such data.

Reference

• Template:Note High water, heat wave, hope floats, Chandrika Mago/TNN, 20-Jun-2005, ToI, Mum (print), pg 14.