The India Meteorological Department (IMD) announced that the southwest monsoon is likely to set in over Kerala on May 26, marking an early arrival compared to the usual onset date of June 1.
The forecast carries a model error of ± 4 days, meaning the onset could occur four days before or after the predicted date. The arrival of the monsoon over Kerala signals the start of India’s four‑month rainy season, which brings nearly 70 per cent of the country’s annual rainfall.
IMD said conditions are favourable for the monsoon to advance over parts of the South Bay of Bengal, the Andaman Sea, and the Andaman and Nicobar Islands within 24 hours. The department noted that the onset over Kerala marks the transition from the hot, dry season to the rainy period.
The weather office uses six predictors for its onset model, including minimum temperatures over northwest India, pre‑monsoon rainfall peaks over the south peninsula, and zonal wind patterns across the Indian Ocean and Pacific regions.
India may receive below‑normal rainfall this year, with an estimated 80 cm against the long‑period average of 87 cm for 1971‑2020. IMD linked the expected shortfall to emerging El Niño conditions, which typically reduce rainfall across the subcontinent.
The monsoon reached Kerala on May 24 last year, and IMD has been issuing operational onset forecasts since 2005.
