Southern peninsular India sees sixth driest October in 123 years, gets 60% less rainfall

Southern peninsular India during October sees rainfall from both the retreating southwest monsoon and the incoming northeast monsoon. But this year, the region remained dry for nearly 25 days in October, IMD officials said. Unlike the past few years, the southwest monsoon ended nearly on time after a 134-day season this year.

One of the major contributors to this poor rainfall was the timing of the northeast monsoon coinciding with other oceanic factors. While the northeast monsoon onset date was realised on October 21, the active Bay of Bengal and cyclogenesis around the same time influenced the monsoon onset.

“This year, the commencement of the northeast monsoon coincided with the genesis of the cyclone Hamoon which crossed the Bangladesh coast. As a rSet featured image 1200×667esult, most of the moisture was dragged away from southern peninsular India. So much so that it even altered the wind flow pattern. Thus, it was a weak northeast monsoon onset,” explained Mrutyunjay Mohapatra, director general, IMD.

According to the IMD, the October rainfall as on October 31 was as follows: coastal Andhra Pradesh and Yanam (18mm, -90 per cent), Rayalaseema (12.7mm, -90 per cent), Tamil Nadu, Karaikal and Puducherry (98.5mm, -43 per cent), south interior Karnataka (64.5mm, -53 per cent) and Kerala (311mm, 1 per cent).

With 2023 being an El Nino year, when combined with the positive phase of the Indian Ocean Dipole (IOD), such rainfall deficits are commonly observed during October and have been previously recorded, added Mohapatra. Notably, 2023, 2016 and 1988, among the six driest October months over the southern peninsula, were El Nino years (see box).

“During El Nino years and the positive IOD phase, there is less rainfall over northern Tamil Nadu and adjoining areas. Whereas, the southernmost areas of Tamil Nadu and Kerala receive good rainfall in October,” he said.

Despite a slow start, the northeast monsoon has picked up during the past two days. During this active phase, widespread good rainfall is predicted over Kerala and Tamil Nadu during the week ahead, the IMD has forecast. “A fresh rainfall spell will affect these states during November 3-5,” the IMD chief official said.

The rainfall forecast for November, too, for this region is promising. The Long Period Average (LPA) of rainfall for south peninsular India during November (based on 1971 to 2020) is about 118.69 mm.

“The monthly rainfall during November over south peninsular India is most likely to be normal and range between 77 – 123 per cent of the Long Period Average, which is 118.69mm (1971-2020 record),” the IMD said in its forecast issued on Tuesday.

Poor rainfall years over south peninsular India

Year – Actual rainfall (mm)

2016 – 50.7

1988 –54.4

1918 – 61.2

1927 – 67.1

1965 – 74.1

2023 – 74.9

Source: IMD

Anjali Marar works at the Raman Research Institute, Bengaluru.