India’s North-East monsoon onset over South peninsula may be delayed
View of pond at The Guindy Race Course after the Northeast monsoon preparedness work in Central and South Chennai by Greater Chennai Corporation
| Photo Credit:
Akhila Easwaran
The India Meteorological Department (IMD) on Tuesday refused to react to speculations over a harsh winter in 2025-26, but predicted that October could have below normal maximum (day) temperature and above normal minimum (night) temperature, mainly because of a well spread out above normal rainfall in most parts of the country.
Briefing media about the outlook over the next three months, IMD Director General Mrutyunjay Mohapatra said that all indications point to a delayed withdrawal of South-West monsoon, and the normal retreat date of October 12 may be missed. But the country is likely to receive above-normal rainfall in October (more than 115 per cent of average 7.54 cm), Mohapatra said.
Linked to SW monsoon withdrawal
As the onset of North-East monsoon is linked to the final withdrawal of S-W monsoon, the arrival of N-E monsoon, too, may get delayed beyond its normal schedule of October 15, scientists said.
Mohapatra said that S-W monsoon has retreated from most parts of north-west India and IMD does not see further progress in withdrawal from its current position for at least next one week.
He said most parts of the country are expected to receive above-normal rainfall during the post-monsoon season (October-December), barring some states in the north-west meteorological subdivision comprising Punjab, Haryana, Rajasthan, Uttar Pradesh and a few other States, where rainfall is likely to be below-normal.
He said rainfall over south peninsular India, comprising five meteorological subdivisions of Tamil Nadu, coastal Andhra Pradesh, Rayalaseema, Kerala and south interior Karnataka, is most likely to be above normal (more than 112 per cent of the long period average of 33.41 cm) during October-December. But, he also said there could be below normal rainfall in a few districts in southern parts of Tamil Nadu.
The IMD’s forecast map also shows many districts of Kerala and a few districts of south Tamil Nadu may have receive below normal rainfall in October.
Asked about the forecast of La Nina developing and impacting Indian rainfall and temperature during winter season, he said current models suggest there is 71 per cent chance of La Nina development during October-December 2025. However, it may be for a short duration and again it may turn to ENSO neutral conditions after January.
The sea surface temperature in the tropical Pacific are continuously measured and when it is between 0.5 Degree C and (-) 0.5 Degree C, it is called El Niño-Southern Oscillation (ENSO) neutral. When the SST falls below -0.5 Degree C, it is called La Nina and when it turns above 0.5 Degree C it is called El Nino.
Mohapatra also said that negative Indian Ocean Dipole (IOD) conditions are likely to continue during the October-December period. Positive IOD and La Nina normally help India to receive good rainfall, though several other factors also contribute.
TNAU outlook
The Tamil Nadu Agricultural University (TNAU) has forecast near-normal rainfall for most districts in the State during the North-East monsoon season from October to December 2025.
The forecast, developed by the Agro Climate Research Centre of TNAU using the Australian Rainman International software, is based on July–August Southern Oscillation Index and sea surface temperature values of the Pacific and Indian Oceans. The predictions are presented at a 60 per cent probability level, said a press release from the varsity.
According to the outlook, Salem, Krishnagiri, Dharmapuri and Karur districts are likely to record below-normal rainfall, with a deviation of 11-19 per cent from the long-term average. The remaining districts are expected to receive normal rainfall, ranging between 0 and 10 per cent deviation.
District-level projections indicate that Chennai, Coimbatore, Tiruppur, Mayiladuthurai, Nagapattinam, Thiruvallur and Tiruvarur may see rainfall slightly above the seasonal average, while most other districts will remain within the normal range.
To mitigate the impact of potential rainfall deficits, TNAU has recommended adaptive strategies such as soil moisture conservation, seed hardening treatments, alternate wetting and drying techniques in rice cultivation, and the use of crop boosters and foliar nutrition at critical stages. Community-level measures like renovating water storage structures and organising cattle camps have also been suggested.
The university emphasised that timely adoption of these practices could help farmers manage water stress and safeguard crop productivity during the upcoming monsoon.
Published on September 30, 2025
