The India Meteorological Department (IMD) has officially confirmed that the southwest monsoon will arrive over Kerala on May 26, marking an early onset compared to the usual arrival date. According to IMD's latest press statement issued on Friday, May 15, the forecast includes a model error of ±4 days, meaning the monsoon could reach Kerala anytime between May 22 to May 30. This represents a significant advancement from the typical arrival timeline, with the department confirming the forecast on Friday. The monsoon has already nearly arrived over the Andaman and Nicobar Islands and the Bay of Bengal, with the IMD noting that it typically takes a 10-day journey onto mainland India from these locations, though various factors such as cyclones can impact this development. The Met department emphasized that this year, the southwest (summer) monsoon is likely to set in over Kerala on May 26 with a model error of ± 4 days, with the advance of the southwest monsoon over the Indian mainland being an important indicator characterizing the transition from the hot and dry season to the rainy season. The monsoon, the primary rain-bearing system, normally arrives in Kerala around June 1 and advances northwards to cover other parts of the country, marking the beginning of the four-month monsoon season (June to September).
The monsoon advancement is being aided by favorable weather conditions, with the monsoon likely to reach the Andaman and Nicobar Islands around May 16 — four days ahead of its normal onset date of May 20. As reported by The Times of India, IMD director Neetha K Gopal explained that under normal conditions monsoon reaches the Andaman and Nicobar Islands around May 20 and Kerala around June 1, creating a typical gap of around 10 days. However, she cautioned that the interval is not fixed, as during the 10-day period fresh low-pressure systems and other weather disturbances can either accelerate or delay the monsoon's advance. The early advance is being supported by a low-pressure area that has formed over the Bay of Bengal, which is expected to move northwestwards or weaken over the next few days, creating favorable conditions for the monsoon current to progress into the Andaman Sea. This dynamic process means that an early onset over the Andaman region does not necessarily mean that Kerala will receive the monsoon ahead of schedule. The IMD has also reported that conditions were favourable for the monsoon to advance over parts of the South Bay of Bengal, Andaman Sea, and Andaman and Nicobar Islands during the next 24 hours.
The forecasted arrival date of May 26 represents a departure from the usual monsoon timeline, with monsoon typically arriving in Kerala around June 1 with a standard deviation of about seven days. Last year, the onset of monsoon occurred on May 24, providing some context for the current forecast and demonstrating the variability in monsoon arrival patterns. As reported by IMD, this marks the earliest monsoon arrival since 2009, highlighting the current year's significance in monsoon timing. The IMD's operational forecasts of monsoon onset over Kerala during the past 21 years (2005-2025) were proved correct except in 2015, with the agency defining 'correct' as the monsoon arriving in a window of four days of the forecast date. In the most recent six-year period (2020-2025), the forecast performance remained close to actual onset dates, with minor variations between predicted and observed arrivals of the monsoon. The forecast is based on an indigenously developed statistical model with a model error of ±4 days, which uses six predictors including minimum temperatures over northwest India, pre-monsoon rainfall peak over the south peninsula, outgoing longwave radiation over the South China Sea and southwest Pacific region, and lower tropospheric zonal winds over the southeast Indian Ocean and northeast Indian Ocean.
With Goa typically receiving the monsoon four to seven days after Kerala, the state could witness rains arriving in early June if weather conditions remain favourable, according to the latest IMD forecast. Alongside the monsoon forecast, the IMD has issued warnings for severe weather conditions across northern India. Heat wave to severe heat wave conditions are likely to prevail over northwest and central India for many days of the week, according to the latest forecast. This dual weather pattern suggests a challenging transition period as the country moves from extreme heat to monsoon conditions, with the heatwave expected to persist for an extended period in these regions. According to M. Ravichandran, Secretary, Ministry of Earth Sciences, The Hindu reports that after the monsoon onset, there will be a good amount of rain for the next five days, though subsequent progress and advance can only be reliably known after subsequent forecasting model runs. As the monsoon progresses northward, relief from scorching summer temperatures is experienced over the areas, marking the transition from the hot and dry season to the rainy season. For farmers, the monsoon's arrival is particularly crucial as timely rains are critical for sowing key kharif crops such as rice, cotton, soybeans and pulses.
Kerala is set to enhance its weather monitoring capabilities with a new X-band Doppler Weather Radar (DWR) being installed at a cost of ₹6 crore at Pulpally in Wayanad. As reported by The Times of India, IMD director Neetha K Gopal confirmed that the radar is in the final stages of installation, and we are aiming to commission it before the onset of the monsoon. The radar, being set up on land provided by the Pazhassiraja College, is a joint initiative of IMD and the Kerala State Disaster Management Authority (KSDMA) with a 30-year lease agreement signed between the organizations. Once operational, the radar will provide high-resolution, real-time weather data, significantly improving rainfall monitoring and short-term forecasting, particularly for northern Kerala and vulnerable hilly regions. Currently, there are two operational DWRs in Kerala -- an S-band DWR in Kochi and a C-band DWR at the Vikram Sarabhai Space Centre in Thiruvananthapuram.
