IMD forecasts below-normal monsoon: 90% of LPA
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UPSC has already asked about this. Read the story with these questions in mind.
IMD’s updated forecast of 29 May 2026 puts southwest monsoon (June–September) rainfall at 90% of the Long Period Average (±4%). The LPA (1971–2020) is 87 cm. There is an 84% probability of below-normal or less rainfall. Neutral ENSO is shifting towards El Niño; the IOD is likely to stay neutral.
- Release
- 29 May 2026, Ministry of Earth Sciences (IMD)
- Seasonal rainfall
- 90% of LPA (±4%); LPA = 87 cm (1971–2020)
- Probability
- 84% for below normal or less
- Method
- Multi-Model Ensemble (MME) since 2021; includes MMCFS
- ENSO / IOD
- ENSO moving towards El Niño; IOD likely neutral
- June outlook
- below-normal rainfall most likely; above-normal heatwave days in many States incl. UP
IMD’s updated 2026 southwest monsoon forecast: what happened?
A below-normal monsoon hits rainfed farms, reservoirs, power and drinking water. IMD now updates its April first-stage call with a May second-stage forecast that also covers regions, June rainfall and heatwaves.
- Below-normal seasonal rain is most likely over most of the country, except some parts of Northwest and Northeast India, eastern peninsular India and adjoining east-central India, and isolated East India pockets, where normal to above-normal is likely.
- June 2026 rainfall is also most likely below normal for the country as a whole.
- Above-normal maximum and minimum temperatures are likely over most parts in June.
- Above-normal heatwave days expected over many parts of Uttar Pradesh, Haryana, Punjab, Bihar, Odisha, Chhattisgarh, Gujarat and Andhra Pradesh, and isolated pockets of Maharashtra, Telangana, Himachal Pradesh and Tamil Nadu; below-normal heatwave days over Rajasthan and Jharkhand.
How does IMD classify seasonal rainfall?
| Category | Range (% of LPA) | Forecast probability (%) | Climatological probability (%) |
|---|---|---|---|
| Deficient | as per IMD table | 60 | 16 |
| Below Normal | >90 to 95 | 24 | 17 |
| Normal | 96 to 104 | 14 | 33 |
| Above Normal | >105 to 110 | 2 | 16 |
| Excess | >110 | 0 | 17 |
What about the four homogeneous regions?
- Tercile forecasts (equal 33.33% climatological probability each) cover Northwest, Central, South Peninsula, Northeast and the Monsoon Core Zone (most rainfed areas).
- Below-normal probabilities are high for Northwest (46%), Central (43%), South Peninsula (45%) and the Monsoon Core Zone (43%); Northeast is more balanced (below 33%, normal 35%, above 32%).
Why does IMD’s updated 2026 southwest monsoon forecast matter?
| Angle | What to note |
|---|---|
| Agriculture | Contingency plans needed for rainfed kharif areas. |
| Water and power | Reservoirs and hydropower face a weaker season. |
| Public health | Heatwave risk in June for several States including UP. |
What are the challenges in IMD’s updated 2026 southwest monsoon forecast?
- 84% probability of a weak season still leaves a 16% chance of normal or better; forecasts are probabilistic.
- El Niño developing through the season adds uncertainty.
- White “no signal” areas on the map mean the model is silent there.
What should be done next on IMD’s updated 2026 southwest monsoon forecast?
- Use IMD weekly and extended-range forecasts for contingency sowing and water rationing.
- State preparedness for heatwaves: cooling shelters, drinking water, health surveillance.
- Watch ENSO and IOD updates through the season.
What can Prelims ask on IMD’s updated 2026 southwest monsoon forecast?
- 2026 SW monsoon (second stage): 90% of LPA ±4%; LPA 87 cm (1971–2020).
- 84% probability of below-normal or less rainfall.
- MME used since 2021; MMCFS is IMD’s model in the ensemble.
- ENSO tipping to El Niño; IOD likely neutral.
- Monsoon Core Zone = most rainfed agriculture areas.
How to write about IMD’s updated 2026 southwest monsoon forecast in Mains
Practice question (15 marks, 250 words): A below-normal monsoon forecast forces hard choices in agriculture and water policy. Discuss with reference to IMD’s May 2026 update.
- Intro: 90% of LPA; 84% probability.
- Science: MME, ENSO/IOD.
- Regional and June/heatwave outlook.
- Impacts: farms, water, power, health.
- Preparedness and early warning.
What should UPPCS aspirants note?
- Above-normal heatwave days in June 2026 are expected over many parts of Uttar Pradesh, as per IMD.
How to use this in Mains
- As per PIB (2026-05-29): IMD's updated forecast puts June–September rainfall at 90% of the LPA (±4%); the LPA (1971–2020) is 87 cm; there is an 84% probability of below-normal or lower rainfall.
- In an El Niño year the kharif crop, reservoir levels and food prices are all at risk.
Quotable data pointIMD's updated forecast puts June–September rainfall at 90% of the LPA (±4%).
PIB: IMD: updated monsoon forecast, 29 May 2026
Exam angle
Prelims: LPA, forecast categories.
Practice MCQs
Original practice questions (not PYQs).
As per IMD's May 2026 second-stage forecast, southwest monsoon rainfall is likely to be
Answer (b) & explanation
PIB (Earth Sciences/IMD), 29 May 2026.
The Long Period Average used by IMD for seasonal monsoon rainfall (1971–2020) is
Answer (b) & explanation
PIB (Earth Sciences/IMD), 29 May 2026.
Questions students ask about this
What is IMD's updated 2026 monsoon rainfall forecast?
90% of the Long Period Average (±4%) for June–September; LPA is 87 cm based on 1971–2020.
How likely is a weak monsoon?
There is an 84% probability of below-normal or less rainfall for the country as a whole.
What are ENSO and IOD doing?
Neutral ENSO is moving towards El Niño; neutral IOD conditions are likely to continue.
Keep studying
Go deeper
Official source: PIB: IMD: updated monsoon forecast, 29 May 2026
facts from cited sources only; faculty review pending