First long-range forecast for 2025 monsoon from India Meteorological Department (IMD) is expected by mid-April, but major global models appear to be converging on prospects for normal to above normal rainfall for the country with Pacific weather pattern providing immediate context for the June-September season.
Table: Pacific state vs monsoon rainfall vs (long-period average 88 cm)
| Year | Pacific state (June-July-August) | Monsoon year | Rainfall (cm) |
|---|---|---|---|
| 2011-12 | La Nina to Neutral | 2011 | 91.5 |
| 2012-13 | Neutral | 2012 | 84.1 |
| 2013-14 | Neutral | 2013 | 94.5 |
| 2015-16 | Neutral | 2015 | 76.5 |
| 2017-18 | Weak La Nina | 2017 | 84.3 |
Weak La Nina to neutral
Most models expect weak La Niña conditions to turn neutral (neither monsoon-killer El Niño or a friendly La Niña) even as monsoon pans across India. No individual model appears to signal rainfall shortfall for any region for any sustained period.
This is despite the country’s past trysts with neutral or La Niña-transitioning-to-neutral phase not being particularly awe-inspiring, as can be seen from adjoining table. One may have to wait and see if any as-yet outlier phenomenon would come to the aid of the monsoon party, judging from the exuberance shown by disparate global models.
Early updates, may change
These are early updates, and subject to change thanks to uncertainty thrown in by so-called spring barrier, during when it is difficult to hazard a guess as to how the Pacific may behave. Global models however suggest June rainfall may mostly hold up across the country while and North-East India could receive its normal quota, welcome surprise unlike past many years.
APEC Climate Centre of South Korean has already come out with normal rainfall during the monsoon based on neutral Pacific. European Centre for Medium-Range Weather Forecasts (ECMWF) concurs, indicating normal rain from March-April-May.
March-April-May covers pre-monsoon for India. ECMWF sees 40-50 per cent probability of normal to above-normal rainfall quantified at above upper tercile (a value higher than upper third of a set of data) for West Coast, with an enhanced 50-60 per cent probability for adjoining parts of Coastal Karnataka and north Kerala.
European agency outlook
April-May-June: This period is projected to have a 50-70 per cent probability of above normal rainfall (above upper tercile) over the South-East Arabian Sea adjacent to Kerala as well parts of central Kerala as monsoon arrives. A similar pattern is indicated for parts of East India and North-East India, which also could see the onset of the monsoon by the Bay of Bengal arm.
May-June-July: Above-normal rainfall (40-50 per cent probability of above upper tercile) for Arabian Sea along the West Coast as well as entire South Peninsula except Tamil Nadu. Parts of East and North-East India too shall receive higher rainfall amounts.
June-July-August: Above-normal (40-50 per cent probability of above upper tercile) for south Kerala, Karnataka, including Tamil Nadu, Andhra Pradesh) and coastal Gujarat with peninsular seas, especially the Bay, staying active. Above-normal rain indicated also for Punjab, Jammu & Kashmir, Ladakh, Himachal Pradesh, Uttarakhand, parts of Uttar Pradesh, Bihar, and West Bengal.
IRI, Columbia University
April-May-June: 40-45 per cent chances above-normal rainfall for parts of West Coast (Konkan & Goa and Coastal Karnataka) and adjoining North Interior Karnataka and Madhya Maharashtra. Above-normal pattern may spread to North Maharashtra, South-West Madhya Pradesh, East Uttar Pradesh, Bihar, Jharkhand, Chhattisgarh, Odisha and West Bengal. Slightly deficient rainfall indicated for South Gujarat (around Surat). Rest of country may witness either normal, normal or just-below normal rainfall)
May-June-July: Above-normal (40-45 per cent) for Kerala, Karnataka, Telangana, Andhra Pradesh and adjoining parts of Central India (Maharashtra), Uttar Pradesh, Bihar and Jharkhand.
June-July-August: Mostly normal except for parts of Punjab, Haryana, Chandigarh, Delhi, Uttarakhand, Konkan & Goa, parts of Telangana and Coastal Andhra Pradesh where it would be up to 40 per cent above normal.
Japan Met Agency
March: Above-normal for South Peninsula with excess for coastal Tamil Nadu and south Kerala. Above-normal for Kerala, Karnataka and rest of Tamil Nadu. Slight deficit for Marathwada, parts of Vidarbha and Punjab, Chhattisgarh, Delhi.
April: Above-normal to excess for Konkan& Goa, Coastal Karnataka and Kerala and above-normal for Madhya Maharashtra, North Interior Karnataka, Tamil Nadu, Rayalaseema, Chhattisgarh, Coastal Andhra Pradesh. Deficit for West Madhya Pradesh, Rajasthan.
May: Normal for most of country and above normal rainfall to excess for Saurashtra an Kachchh.
June: Normal rainfall for country except parts of northern Tamil Nadu.
July: Normal rainfall except slight deficit for northern Kerala. Above-normal for Gujarat, Saurashtra and Kachchh, southern Madhya Pradesh, Vidarbha, parts of Andhra Pradesh, Jammu & Kashmir, Ladakh, Punjab, Himachal Pradesh, and Uttarakhand.
UK Met Office
March-April-May: For pre-monsoon, 40-60 per cent probabilities for above-normal rainfall (lower of three tercile categories) for southern half of the country and 0-40 per cent for north and west.
April-May-June: The 40-60 per cent probabilities for above normal rainfall spread to eastern and western parts to the country apart from south, while this lower percentile category is confined to northern most parts.
May-June-July: Entire country will come under the category of 40-60 per cent probabilities for above-normal rainfall.