Indian Climate and Seasons

'Rainfall generally increases away from the equatorial region both northwards and southwards up to about 30^o north and south' is an incorrect statement. The equatorial regions receive more rainfall because equatorial regions are located in Torrid Zone, which receives more heat than other zones, and tropical regions are located near the equator. Due to the heat, water evaporates much more times than other areas, thus bringing more rainfall. 

The western disturbances which cause winter rain in India originate in West Asia. Western Disturbance is the term used in India, Pakistan, Bangladesh and Nepal to describe an extra tropical storm originating in the Mediterranean, that brings sudden winter rain and snow to the northwestern parts of the Indian subcontinent. The weather conditions during winter are generally influenced by the distribution pattern of pressure in Central and West Asia. 

During the period of the South-west Monsoon, Tamilnadu remains dry because it lies parallel to the Coromandal coast. Tamil Nadu Coast remains mostly dry as it falls in the rain-shadow area of the Arabian Sea branch and is parallel to the Bay of Bengal branch. Rainfall does not take place continuously. After a few days of rainfall, a short spell of dry days is quite common. Thus, the Southwest monsoon season spreads over June to September in most of parts of India.

The monsoon climate is defined by a distinct seasonal reversal of winds, which brings heavy rainfall during the summer months and a dry winter season.

The jute plant is cultivated in rainy season in Bihar and Assam.

In western and southern regions, the hottest month is April; for northern regions, May is the hottest month. Temperatures average around 32–40 °C (90–104 °F) in most of the interior.

 The wind system in the equatorial area is known as trades.

High mean temperature, high relative humidity and heavy rainfall (well distributed all over the year) are the characteristic features of the Equatorial region.

The retreating monsoon withdraws itself from North-West India to Bengal and then to Kerala. Withdrawal or the retreat of the monsoon is a more gradual process. The withdrawal of the monsoon begins in northwestern states of India by early September. By mid-October, it withdraws completely from the northern half of the peninsula. The withdrawal from the southern half of the peninsula is fairly rapid. By early December, the monsoon has withdrawn from the rest of the country.

India has endless growing season because temperatures throughout the year are favourable for growth of plants.

The belt of the highest temperature, in the month of March, lies in southern and central parts of the Deccan Plateau.

Statement 1 is incorrect. El Niño/La Niña-Southern Oscillation, or ENSO, is a quasi-periodic climate pattern that occurs across the tropical Pacific Ocean roughly every five years. It is characterised by variations in the temperature of the surface of the tropical eastern Pacific Ocean—warming or cooling known as El Niño and La Niña, respectively. The two variations are coupled: the warm oceanic phase, El Niño, accompanies high air surface pressure in the western Pacific, while the cold phase, La Niña, accompanies low air surface pressure in the western Pacific. Statement 2 is also incorrect. Direct effects of El Niño resulting in drier conditions occur in parts of Southeast Asia and Northern Australia, increasing bush fires and worsening haze and decreasing air quality dramatically. Drier than normal conditions are also generally observed in Queensland, inland Victoria, inland New South Wales and eastern Tasmania from June to August. During La Niña years, the formation of tropical cyclones, along with the subtropical ridge position, shifts westward across the western Pacific ocean, which increases the landfall threat to China.

 Thiruvananthpuram has lower temperature than Mumbai in May because of higher rainfall in summer. Since it is nearer to equator it has higher temperature than that of Mumbai in January.