NEW DELHI: Monsoon is likely to arrive in Kerala on May 26, IMD said Friday, forecasting an early start to the rainy season in India. Monsoon normally sets in over Kerala on June 1, give or take seven days.“This year, the southwest (summer) monsoon is likely to set in over Kerala on May 26 with a model error of ± 4 days,” the met department said, noting that its operational forecasts of the date of onset over Kerala during the past 21 years (2005-2025) were proved to be correct except in 2015. Early or late arrival has no bearing on overall monsoon performance or distribution.Last year, monsoon arrived over Kerala eight days in advance, on May 24.IMD has forecast ‘below normal’ rains this year amid El Nino riskThe onset of monsoon in Kerala marks the arrival of the southwest monsoon in the Indian mainland. It is an important indicator characterising the transition from hot and dry conditions to the rainy season.The met department has already predicted ‘below normal’ monsoon rainfall this year over many parts of the country amid the growing risk of El Nino, which is invariably associated with harsher summer and weaker monsoon in south Asia.

Meanwhile, IMD on Friday said conditions were favourable for the advance of southwest monsoon over parts of south Bay of Bengal, Andaman Sea and Andaman & Nicobar Islands in the next 24 hours.IMD has been issuing operational forecasts for the date of monsoon onset over Kerala from 2005 onwards, using an indigenously developed statistical model with a model error of ± 4 days.The six predictors used in the models are: minimum temperatures over north-west India, pre-monsoon rainfall peak over south Peninsula, outgoing long wave radiation (OLR) over south China Sea, lower tropospheric zonal wind over equatorial southeast Indian Ocean, outgoing long wave Radiation (OLR) over southwest Pacific Ocean, and lower tropospheric zonal wind over equatorial northeast Indian Ocean.