The India Meteorological Department (IMD) has released its highly anticipated Long Range Forecast for the 2025 Southwest Monsoon Seasonal Rainfall, predicting an “above normal” monsoon for India. This forecast, issued on April 15, 2025, indicates a seasonal rainfall of 105% of the Long Period Average (LPA), with a margin of error of ±5%. This positive outlook is supported by several key factors, including the persistence of neutral El Niño-Southern Oscillation (ENSO) conditions, coupled with La Niña-like atmospheric patterns, and a neutral Indian Ocean Dipole (IOD). Additionally, below-normal snow cover in Eurasia over the past three months is believed to potentially enhance the Indian monsoon. The IMD’s forecast, based on both dynamical and statistical models, signals a strong probability of above-normal rainfall, promising significant implications for agriculture and the overall economy. The department will issue an updated forecast in late May 2025, providing further clarity as the monsoon season approaches.
Forecast for the 2025 Southwest Monsoon Season (June–September) rainfall: India set for an ‘above normal’ Monsoon this year, says IMD
The forecast based on both dynamical and statistical models suggests that quantitatively, the monsoon seasonal rainfall is likely to be 105% of the Long Period 3 3
Average (LPA) with a model error of ± 5%. The LPA of the season rainfall over the country as a whole for the period 1971-2020 is 87 cm.
The five category probability forecasts for the Seasonal (June to September) rainfall over the country as a whole are given below, which suggests that there is strong probability (59%) of southwest monsoon seasonal rainfall likely to be in the above normal category or higher (>104% of LPA).
The MME forecast for the southwest monsoon season rainfall during 2025 was prepared based on the April initial conditions of a group of coupled climate models which have higher 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 (June to September) rainfall during 2025 is shown in Fig.1. The spatial distribution suggests above-normal seasonal rainfall is very likely over most parts of the country except some areas over Northwest India, Northeast India and South Peninsular India, where below-normal rainfall is likely. The white-shaded areas within the land area represent no signal from the model with equal probabilities for all the tercile categories of rainfall.
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 as a whole in two stages. The first stage forecast is issued in April and the second stage or updated forecast is issued by the 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.
As per the new LRF strategy, the first stage forecast issued in middle of April consists of the 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.
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 as a whole, 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 state forecast.
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