**Executive Summary**
This report provides the first-stage long-range forecast for the 2026 Southwest Monsoon (June–September) seasonal rainfall in India. Current data indicates that rainfall is most likely to be below normal at 92% of the Long Period Average (LPA). An updated second-stage forecast, including regional predictions, is scheduled for release in the last week of May 2026.
**Key Points / Main Content**
**Rainfall Projections**
* **Seasonal Outlook:** Rainfall is predicted to be below normal, estimated at 92% of the LPA with a model error of ± 5%.
* **LPA Reference:** The Long Period Average for seasonal rainfall is 87 cm (based on 1971–2020 data).
* **Probability Categories:** There is a 35% probability of deficient rainfall (<90% of LPA) and a 31% probability of below-normal rainfall (90–95% of LPA). Probabilities for "Above Normal" and "Excess" rainfall are lower than climatological averages.
**Regional Distribution**
* **General Trend:** Below-normal rainfall is likely over many parts of the country.
* **Exceptions:** Normal to above-normal rainfall is anticipated in some areas of Northeast India, Northwest India, and South Peninsular India.
**Climate Drivers and Conditions**
* **ENSO Conditions:** Current weak La Niña conditions are transitioning to ENSO-neutral. However, models suggest the development of El Niño conditions during the monsoon season.
* **Indian Ocean Dipole (IOD):** Conditions are currently neutral, but a positive IOD is forecast to develop toward the end of the monsoon season.
* **Snow Cover:** Northern Hemisphere and Eurasian snow cover from January to March 2026 was slightly below normal, which historically has an inverse relationship with monsoon rainfall.
**Forecasting Methodology**
* **Two-Stage Strategy:** The first forecast is issued in April; the second update occurs in late May.
* **Systems Used:** The forecast utilizes the Multi-Model Ensemble (MME) and the Monsoon Mission Climate Forecast System (MMCFS), combining dynamical and statistical systems.
**Impact Analysis**
**India Meteorological Department (IMD)**
**Impact**
The IMD is tasked with the ongoing monitoring of evolving sea surface temperatures in the Pacific and Indian Oceans and atmospheric circulation features.
**Action Required**
The IMD must issue an updated second-stage forecast in the last week of May 2026, followed by monthly rainfall forecasts at the end of June, July, and August.
**National Stakeholders (Agriculture, Water Management, and Policy Makers)**
**Impact**
The forecast of "below normal" rainfall (92% of LPA) suggests potential water and agricultural challenges for most of the country, excluding specific regions in the Northeast, Northwest, and South Peninsula.
**Action Required**
Stakeholders should prepare for potential rainfall deficiencies and closely monitor the updated regional and monthly forecasts provided by the IMD to adjust planning.
Key Entities Referenced
India Meteorological Department (IMD): The primary agency responsible for issuing long-range forecasts for the southwest monsoon and implementing seasonal forecasting strategies.
Monsoon Mission Climate Forecast System (MMCFS): A specialized dynamical forecasting system used to predict climate conditions, including El Niño developments and seasonal rainfall.
Ministry of Earth Sciences: The nodal ministry that oversees meteorological operations and the official release of national monsoon forecasts.
Multi-Model Ensemble (MME): A forecasting strategy based on coupled global climate models from various prediction centers used to prepare spatial distribution rainfall forecasts.
Long Period Average (LPA): The official statistical benchmark (currently 87 cm based on 1971-2020 data) used to categorize monsoon rainfall as normal, deficient, or excess.
Ministry of Earth Sciences
Long Range Forecast For the 2026 Southwest
Monsoon Season Rainfall
The 2026 southwest monsoon seasonal (June to September)
rainfall over the country is most likely to be below normal (95-
90% of the Long Period Average (LPA)
Seasonal rainfall over the country is likely to be 92% of LPA
with a model error of ± 5%
The LPA of the seasonal rainfall over the country based on
the period of 1971-2020 is 87 cm
Weak La Niña–like conditions are transitioning to ENSO-
neutral conditions over the equatorial Pacific
Atmospheric circulation features across the tropical Pacific
remain consistent with weak La Niña–like conditions
The Monsoon Mission Climate Forecast System (MMCFS)
suggests the development of El Niño conditions during the
SW Monsoon season
Neutral Indian Ocean Dipole (IOD) conditions are present over
the Indian Ocean and the latest Climate models forecast
indicates that the positive IOD conditions are likely to
develop towards the end of the southwest monsoon season
The northern hemisphere snow cover extent during the last
three months (January to March 2026) was slightly below
normal
Winter and spring snow cover extent over Northern
Hemisphere as well as Eurasia has a general inverse
relationship with the subsequent southwest monsoon
seasonal rainfall over the countryIMD will issue the updated forecasts for monsoon season
rainfall in the last week of May 2026
Posted On: 13 APR 2026 5:41PM by PIB Delhi
Since 2003, India Meteorological Department (IMD) has been issuing the operational long-range forecast
(LRF) for the southwest monsoon seasonal (June-September) rainfall averaged over the country in two
stages. The first stage forecast is issued in April and the second stage or update forecast is issued bythe
end of May. In 2021, IMD has implemented a new strategy for issuing monthly and seasonal operational
forecasts for the southwest monsoon rainfall over the country by modifying the existing two stage
forecasting strategy. The new strategy uses both dynamical and statistical forecasting system. Multi-Model
Ensemble (MME) forecasting system based on coupled global climate models (CGCMs) from different
global climate prediction centres, including IMD’s Monsoon Mission Climate Forecast System (MMCFS)
are used in dynamical forecast system.
As per the new LRF strategy, the first stage forecast issued in middle of April consists of quantitative and
probabilistic forecasts for the country as a whole, and the spatial distribution of probabilistic forecasts for
the tercile categories (above normal, normal, and below normal) of the seasonal (June-September) rainfall
over the country.
In the second stage forecast issued around end of May consist of update for the seasonal rainfall forecast
issued in April along with the probabilistic forecasts for the seasonal rainfall over the four homogenous
regions of India (northwest India, central India, south Peninsula, and northeast India) and monsoon core
zone (MCZ). In addition, quantitative and probabilistic forecasts for the country, and the spatial
distribution of probabilistic forecasts for the tercile categories (above normal, normal, and below normal)
of the June rainfall over the country are also issued during the second stage forecast.
In continuation to the above forecasts, monthly rainfall forecast is issued around end of June, July, and
August respectively for the subsequent one month. In addition, quantitative and probabilistic forecasts for
the country, and the spatial distribution of probabilistic forecasts for the tercile categories for the second
half of the season rainfall is issued around end of July along with the forecast for August.
1.Forecast for the 2026 Southwest monsoon Season (June–September) rainfall over the country.
The forecast based on both dynamical and statistical models suggests that quantitatively, the monsoon
seasonal rainfall is likely to be 92% of the Long Period Average (LPA) with a model error of ± 5%. The
LPA of the seasonal rainfall over the country for the period 1971-2020 is 87 cm.
The five-category probability forecast for the Seasonal (June to September) rainfall over the country is
given below. The forecast indicates that the probabilities for both below normal and deficient rainfall
categories are higher than their respective climatological probabilities. The forecast probabilities for the
“Above Normal” and “Excess” rainfall categories are lower than their respective climatological
probabilities. Overall, the Southwest Monsoon seasonal rainfall over the country is most likely to be
below normal (90–95% of LPA).
Category Rainfall Range Forecast Probability Climatological
(%)
(% of LPA) Probability (%)Deficient < 90 35 16
Below Normal 90 - 95 31 17
Normal 96 -104 27 33
Above Normal 105-110 6 16
Excess > 110 1 17
The MME forecast for the 2026 southwest monsoon seasonal rainfall was prepared based on the April
initial conditions and using a group of coupled climate models that having highest prediction skill over the
Indian monsoon region.
The spatial distribution of probabilistic forecasts for tercile categories (above normal, normal, and below
normal) for the seasonal rainfall (June to September) is shown in Fig.1. The spatial distribution suggests
that the below-normal seasonal rainfall is most likely over many parts of the country except some areas
over Northeast, Northwest, and South Peninsular India, where normal to above-normal rainfall is likely.
The white-shaded areas within the land area represent no signal from the model.
2.Sea Surface Temperature (SST) Conditions in the equatorial Pacific & Indian Oceans
At present, Weak La Niña–like conditions are transitioning to ENSO-neutral conditions over the equatorial
Pacific. However, some atmospheric circulation features across the tropical Pacific remain consistent with
weak La Niña–like conditions. The latest forecasts from the Monsoon Mission Climate Forecast System
(MMCFS) suggest that ENSO-neutral conditions are most likely to continue during the April to June 2026
season. The Monsoon Mission Climate Forecast System (MMCFS) suggests the development of El Niño
conditions during the SW Monsoon season.
Currently, neutral Indian Ocean Dipole (IOD) conditions are present over the Indian Ocean and the latest
Climate models forecast indicates that the positive IOD conditions are likely to develop towards the end of
the southwest monsoon season.
As sea surface temperature (SST) conditions over the Pacific and the Indian Oceans are known to have a
strong influence on the Indian monsoon, IMD is carefully monitoring the evolution of sea surface
conditions over these Ocean basins.
3.Snow Cover over the Northern Hemisphere
The northern hemisphere snow cover extent during the last three months (January to March 2026) was
slightly below normal. Winter and spring snow cover extent over Northern Hemisphere as well as Eurasia
has a general inverse relationship with the subsequent southwest monsoon seasonal rainfall over the
country.Fig.1.Probability forecast of tercile categories* (below normal, normal, and above normal) of the seasonal
rainfall over India during the 2026 southwest monsoon season (June -September). The figure illustrates
the most likely categories as well as their probabilities. The white shaded areas represent no signal from
the model. (*Tercile categories have equal climatological probabilities, of 33.33% each).
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