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Informist, Wednesday, Nov. 26, 2025

 

By Shreya Shetty and Abhijit Doshi

 

MUMBAI – The La Nina event this year, onset of which has already begun, is unlikely to have a major impact on Indian weather and agriculture, according to former Air Vice Marshal G.P. Sharma, who is president of meteorology and climate change at Skymet. The weather phenomenon is expected to be short-lived, defying norms of its normal duration and intensity. As such, it is unlikely to impact the severity of winter and south peninsular rainfall, or the northeast monsoon, he said, adding that neutral El Nino Southern Oscillation conditions are likely to return in Feb-March.

 

The El Nino-Southern Oscillation refers to the fluctuation between El Nino and La Nina conditions in the Pacific Ocean. El Nino is linked to drier and hotter weather in India while La Nina results in more favourable rainfall.

 

Between La Nina and El Nino, the latter has a stronger correlation with Indian weather, Sharma explained. This is mainly due to the periodical difference in their occurrences--El Nino has a larger probability of developing during summer monsoon and southwest monsoon, while La Nina is most likely to develop during northeast monsoon and the winter.

 

As most agricultural activities take place during the southwest monsoon season, the correlation between an El Nino event and Indian agriculture is stronger, Sharma said. According to the US' Climate Prediction Centre, chances of an El Nino event are 35% in Jul-Aug-Sept next year. However, it is only a preliminary reading, and a more reliable forecast will only come in February, he said.

 

The following are edited excerpts from the interview:

 

Q. There are conflicting reports about La Nina conditions being currently active. What is your assessment? If you think it is active, what is the basis of your opinion?

A. La Nina and El Nino, they have become a little more frequent in the recent past. If you remember, in the last six years, we had triple La Nina in 2020, 2021, and 2022, followed by El Nino in 2023, and again, a short stint of La Nina in 2024.

 

A similar case is building up again for 2025 as well. Conditions are favourable for La Nina to come up, for which the process has already started. However, in normal circumstances, La Nina and El Nino events last for about 9 to 12 months. They start sometime after Indian Spring or Northern Hemispheric Spring. They go on through the monsoon months. They peak around early post-monsoon, around September, October, and November. And by the time you reach fall of the year, they start declining.

 

But La Nina events last year and this year also defied the norms. It is neither following the normal period, nor is it following the duration as such. The last La Nina event, which we had in 2024, lasted for barely three months or so.

 

And it looks like this year's La Nina also, which is developing over the equatorial Pacific, its duration will also be small. A short stay of La Nina, it could be just about three to four months or so. By the time we go into the winter next year, say after February 2026 or at best maybe March 2026, once again, the conditions should turn neutral.

 

Q. Why are different weather models at the global level giving different readings regarding the La Nina event currently?

A. Now, Australian standard or Europe methodology standards are different from what the USA's CPC (Climate Prediction Centre) follows. For CPC, El Nino, the standards are plus or minus 0.5 degrees Celsius, and for IOD (Indian Ocean Dipole), it is plus or minus 0.4 degrees Celsius. The Australian Bureau for El Nino and La Nina, their standard markers and the threshold value is plus minus 0.8 degrees Celsius.

 

Q. What is the impact of the ongoing La Nina event on agriculture?

A. See, between El Nino and La Nina, El Nino has got a stronger correlation with the Indian weather condition. La Nina does have a connection, but the correlation is not as strong as El Nino.

 

Firstly, the La Nina conditions as such, the threshold is barely reaching (-) 0.5 degrees Celsius, and my estimate is that it may not go beyond minus one degree Celsius. Means, La Nina is not going to be strong. La Nina is not going to last long. So, it will be for a brief period, it will be a weak event.

 

So, putting these two things in perspective, I do not expect any large impact of this La Nina event on the Indian weather conditions. As such La Nina comes up in the winter months. The peak of post-monsoon season is already over now. Yes, three to four weeks of December will be there, but by the time mid-December comes, that season also, the impact of La Nina starts losing its steam. So, practically what I say is, I do not see any large impact of La Nina as far as south peninsular rains are concerned.

 

And for the severity of winters, I find that it should be on the shallow side due to a shallow La Nina. So it may not impact the severity of winters and rainfall so far, both put together in the month of January.

 

Q. Negative Indian Dipole Conditions are also prevailing currently. How does that impact the northeast monsoon and temperatures alongside La Nina?

A. Indian Ocean Dipole has gone to negative, its values reached even as close as (-) 2 degrees Celsius, which is a strong negative event. But the forecast is that the margin should reduce. In the month of December, it should turn even neutral.

 

Q. In your recent article, you suggested we could see a brief El Nino event next year. Could you briefly specify the reasons behind this prediction?

A. It's a very preliminary reading at this stage, because all the models have some limitations. With the lead time, their performance, their skill degrades. If we are talking about next year also, which is June to September, there is still a lot of time to go. It is too early to predict now. But sometimes you have some foreshadowing based on the prediction of these models.

 

But to read in between the lines, at this stage, about the likely condition of El-Nino during the Indian monsoon, I think it will be a little pre-emptive. Models give a forecast for around the next nine months or so. The El Nino prediction was on the far end of that model, which was indicating some indications that maybe the (El Nino) component may increase.

 

I will say we have to wait because the forecast definitely is better when you are closer to the event. The farther from the event, if you are there, the reliability is less. The best of these forecasts come in the month of February.

 

Q. This year, many expect a fall in agricultural output due to excessive rainfall during the southwest monsoon. Do you think our agriculture sector is not equipped to handle adverse weather yet, or did we just have an abnormal monsoon this year?

A. Nowadays, the total seasonal rainfall is 868 mm. There was a time when the rainfall was 889 mm, around 20 years ago or so. That means the rainfall has reduced by almost about 30 mm. Once the normal rainfall reduces, you reduce the seasonal rainfall, the chances of the season to have a normal or above-normal, they grow.

 

In the last six years, we have seen either normal or above normal monsoon, barring 2023. So, more number of normal or above -normal years are there.

 

The effect on agriculture depends on the belt which experienced such excess rainfall. Take the pocket of Bihar, it was a drought through and through, right till the end of the season. It was only in the month of October when the monsoon started withdrawing from other parts that Bihar got some rainfall.

 

So variation of monsoon is an inbuilt characteristic. Sometimes it gives excess rainfall over some pockets which was expected this time. Parts of Maharashtra, parts of Gujarat, yes, they had excess of rainfall. Even the state of Rajasthan, which is otherwise known for having deficit rainfall, was also flooded on a few occasions.

 

Intra-seasonal variation is an inbuilt characteristic of monsoon. Intra-seasonal, in any case, from one year to the next year, variations are there. But inter-seasonal, within one season itself, the variation over different parts is an inbuilt characteristic.

 

Q. While the timeliness of rains is important for the farm sector and therefore for the economy, so is its regional distribution. Do you have any measure--like an index--on this variable?

A. Unfortunately, we do not have that index as such. But yes, you are very right. Temporal and spatial distribution are both equally important. We should have rain when they are required and the quantum of rain should be what we need at that point of time. But then, unfortunately, it is not. At the end of the season, we just look at the figure. How much was there? 107%, 106% or 108% (above normal rainfall). That's what we feel happy about that it has ended. Notwithstanding, the distribution of the monsoon rainfall over the country is all important. It's always there. Which we, many a time, keep ignoring.

 

Q. The Indian Institute of Tropical Meteorology is expected to launch an artificial intelligence-powered application to predict weather to aid the agriculture sector. Does Skymet plan to work on something similar?

A. We were the first one to come up with the AI forecast. That was about three years back. We did come up with a model where you can ask anything whether it is going to rain in Uttarakhand today or whether it is going to rain at so and so place today.

 

But then you see, introduction of AI in the field of weather, it has got both plus and minus, I will say. AI has got its own limitations. The human intervention and the expertise, they can never be overtaken by any of these things. Expertise matters a lot and the more the experience an individual has and is utilising it in the field of forecasting, the better the prediction can be.  End

 

Edited by Ashish Shirke

 

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