Early Arrival of Monsoon 2025? IMD Forecasts Onset of Monsoon by May 27 Over Kerala
New Delhi, 10 May 2025 — The India Meteorological Department (IMD), under the Ministry of Earth Sciences (MoES), has officially forecasted that the southwest monsoon is likely to make its onset over Kerala on 27th May 2025, with a model error margin of ±4 days. This forecast marks the beginning of the transition from India’s hot and dry summer season to the much-awaited rainy season.
The onset of the southwest monsoon over Kerala is a critical climatological event for India, signaling relief from scorching heat and the beginning of agricultural activities across many parts of the country. Traditionally, the monsoon sets in over Kerala around 1st June, with a standard deviation of about seven days.
IMD has been issuing operational onset forecasts since 2005 using an indigenously developed, state-of-the-art statistical model. This model, which has a historical accuracy record (barring a single miss in 2015), relies on six key meteorological predictors:
- Minimum temperatures over Northwest India
- Pre-monsoon rainfall peaks over the southern Peninsula
- Mean sea level pressure over the subtropical Northwest Pacific Ocean
- Outgoing longwave radiation (OLR) over the South China Sea
- Lower tropospheric zonal wind over the Northeast Indian Ocean
- Upper tropospheric zonal wind over the Indonesian region
The reliability of the IMD’s model has been consistent, with correct predictions in 19 out of the last 20 years. Even in the past five years (2020–2024), the onset forecasts were accurate, confirming the robustness of the forecasting system.
दक्षिण-पश्चिम मानसून का पूर्वानुमान #monsoon #monsoon2025 #SouthwestMonsoon #MonsoonForecast@moesgoi @ndmaindia @DDNational @airnewsalerts pic.twitter.com/esNRl9xJCE
— India Meteorological Department (@Indiametdept) May 10, 2025
This year’s prediction, placing the onset around 27th May, provides crucial lead time for farmers, disaster management authorities, and water resource planners to prepare for the incoming monsoon season. As the southwest monsoon progresses northward, it is expected to bring relief from the high summer temperatures currently being experienced across the country.
The IMD will continue to monitor the evolving conditions and provide further updates as necessary.
