NEW DELHI: The southwest (summer) monsoon set in over Kerala on Thursday, three days after its normal onset date, India Meteorological Department (IMD) said. The monsoon normally arrives in Kerala on June 1, marking the beginning of the four-month rainy season as well as kharif crop sowing operations in India. This is only the second time in the past 22 years that IMD’s operational forecast of the monsoon’s onset date over Kerala has been off the mark – the Met department had earlier predicted May 26 as the onset date, with a model error of +/- 4 days. The last time its prediction proved wrong was in 2015. IMD has been issuing operational forecasts for the date of monsoon’s onset over Kerala from 2005, using an indigenously developed statistical model.“The southwest monsoon has further advanced into the remaining parts of southwest and southeast Arabian Sea… Lakshadweep islands, Kerala and Mahe; some parts of Karnataka and Tamil Nadu; the remaining parts of Comorin area; southeast Bay of Bengal… on June 4,” said IMD. The Met department added, “Conditions are favourable for further advance of southwest monsoon into some more parts of central Arabian Sea, Goa, some parts of Maharashtra and Andhra Pradesh, some more parts of Karnataka, the remaining parts of Tamil Nadu… and some parts of the northeastern states during the next two-three days.” Last year, the monsoon arrived over Kerala on May 24, eight days in advance. Early or late arrival of the monsoon has no impact on overall quantitative or spatial rainfall.