North east monsoon South Peninsular India consisting of five meteorological subdivisions (Tamil Nadu, Puducherry & Karaikal, Coastal Andhra Pradesh & Yanam, Rayalaseema, Kerala & Mahe, and South Interior Karnataka) receives about 30% of its annual rainfall during the northeast monsoon season (October to December). Tamil Nadu, Puducherry, and Karaikal receive approximately 48% of their annual rainfall during the northeast monsoon season. Recognising the significance of this period, IMD has been issuing seasonal rainfall forecasts for the south peninsula using statistical models since 1998 and continues to enhance the skill of these forecasting systems. In 2021, IMD adopted a new strategy for issuing monthly and seasonal operational forecasts for rainfall over the country. This approach combines the existing statistical forecasting system with a newly developed Multi-Model Ensemble (MME)–based system. The MME technique use coupled global climate models (CGCMs) from various international climate prediction and research centers, including IMD’s own Monsoon Mission Climate Forecast System (MMCFS). Using this strategy, IMD issues a range of seasonal and monthly forecasts for rainfall and temperature (Maximum & minimum). The rainfall forecast for the post-monsoon season (October to December 2026) is provided by IMD during end of September. Probabilistic Forecast for the rainfall during October to December (OND) 2026 The rainfall averaged over south Peninsular India during post-monsoon season (October to December (OND)) is most likely to be normal (88-112% of Long Period Average (LPA)). The LPA of rainfall over the South Peninsular India during the post-monsoon season based on data of 1971 to 2020 is about 334.1 mm. The probability forecast indicates that most parts of the country are expected to receive below-normal rainfall, except some areas of Northwest India and southern parts of the peninsular India, where rainfall is likely to be normal to above-normal. Below-normal rainfall during the Rabi season could adversely affect soil moisture, water availability, irrigation requirements, and agricultural productivity, while increasing the likelihood of dry spells, moisture stress, and reduced recharge of reservoirs and groundwater. Although extreme weather events are generally less frequent during this season, their occurrence and localized impacts cannot be ruled out.In view of these potential risks, anticipatory preparedness and mitigation measures may be initiated well in advance. IMD's early warning and advisory services, including weather forecasts, Impact-Based Forecasts (IBF), and risk-based advisories, may be effectively utilized to support timely decision-making. Authorities and stakeholders are advised to regularly assess water availability, optimize irrigation resources, promote water conservation and efficient water use, and implement appropriate agricultural contingency measures. Timely action based on IMD advisories can help strengthen preparedness, improve resource management, and minimize potential impacts on agriculture and livelihoods. Probability forecast of tercile categories* (below normal, normal, and above normal) of rainfall over India during October to December, 2026 period. The figure illustrates the most likely categories as well as their probabilities. The white shaded areas within the land area represent no signal from the model. The dotted areas receive low rainfall during the season as per climatology. *Tercile categories have equal climatological probabilities, of 33.33% each. Onset of NE monsoon 2026 The Northeast Monsoon rainfall activity has commenced over Tamil Nadu, Puducherry & Karaikal, Coastal Andhra Pradesh, Rayalaseema, South Interior Karnataka and Kerala Mahe on 15th October 2026. Cyclone warnings To view Cyclone warnings, click here. Flash flood warning Bulletin To view Flash flood warning Bulletin, click here. District-wise warnings To view district-wise warnings, click here. Marine Forecast/Warnings for Fishermen To view Marine Forecast/Warnings for Fishermen, click here. Source : IMD