Monsoon to Arrive Over Kerala on May 27: IMD Forecast
The India Meteorological Department (IMD) on Saturday forecast that the southwest monsoon is likely to arrive over Kerala on May 27, 2025, with a model error margin of ±4 days.
In its annual forecast, the IMD has projected the onset of the southwest monsoon over Kerala by May 27 this year. The forecast suggests an early arrival, considering the monsoon typically hits the state around June 1. The model includes a standard deviation of four days.
According to the IMD’s statement, “This year, the southwest monsoon is likely to set over Kerala on 27th May with a model error of ± 4 days.” The forecast is based on a statistical model developed by the department using six key climatic indicators.
The IMD has been issuing operational forecasts for the onset of the monsoon over Kerala since 2005. These predictions have generally proven accurate, with only one exception in 2015. Data from the last five years (2020–2024) shows close alignment between forecast and actual onset dates.
For instance, in 2023, the monsoon was predicted to begin on June 4 and actually arrived on June 8. In 2022, the forecast of May 27 closely matched the actual onset on May 29.
The forecast model incorporates six predictors:
- Minimum temperatures over northwest India
- Pre-monsoon rainfall over south Peninsular India
- Mean sea level pressure over the subtropical northwest Pacific Ocean
- Outgoing Longwave Radiation over the south China Sea
- Lower tropospheric zonal wind over the northeast Indian Ocean
- Upper tropospheric zonal wind over the Indonesian region
The IMD noted that these indicators help accurately predict the monsoon’s advancement, which is vital for agriculture, water management, and disaster preparedness.
The onset of the southwest monsoon over Kerala signals the start of India’s primary rainy season. It is a critical meteorological milestone that influences crop sowing, reservoir levels, and economic activities across the subcontinent. A timely monsoon is especially crucial for India’s agricultural sector, which still relies heavily on rain-fed irrigation.
Meteorologists say the early monsoon, if it materializes, could benefit agricultural planning and ease water shortages in several regions. “An early onset over Kerala generally suggests good progress northward, provided there are no significant delays in its advancement,” said a senior IMD scientist.
The IMD will continue to monitor conditions and release updates on the monsoon’s progression through May and June.
