The onset of Southwest Monsoon 2017 over Kerala will probably be on May 30, with a system error of 4 days, the India Meteorological Department (IMD) said on Tuesday

The statement, released by the IMD office, said that the start of Southwest Monsoon across Kerala signals the arrival of monsoon over the Indian subcontinent and start of rainy season over the region.

The date regarding the normal monsoon onset over Kerala is June 1 and since 2005, the IMD began to issue operational forecasts for the date of monsoon onset over Kerala.

“For this an indigenously developed statistical model with a model error of 4 days is used. The model uses the following six predictors which includes minimum temperatures over northwest India, pre-monsoon rainfall peak over south peninsula, outgoing long wave radiation over south China Sea, lower tropospheric zonal wind over southeast Indian Ocean, upper tropospheric zonal wind over the east equatorial Indian Ocean, and outgoing long wave radiation over the south-west Pacific region,” said the statement.

The forecasts regarding the monsoon onset issued during the past 12 years (2005-2016) were turned out to be correct for several years except 2015.