The onset of monsoon over Kerala is likely to be delayed this year, predicting its arrival on June 4, four days after the normal date predicted on June 1, India Meteorological Department (IMD) said.

“Southwest monsoon normally sets in over Kerala on June 1 with a standard deviation of about 7 days. India Meteorological Department (IMD) has been issuing operational forecasts for the date of monsoon onset over Kerala from 2005 onwards. An indigenously developed state-of-the-art statistical model with a model error of +- 4 days is used for the purpose,” IMD stated. Last year, the monsoon over Kerala occurred on May 29, two days after IMD’s prediction on May 27. The operational forecasts of the date of monsoon onset over Kerala during the past 18 years (2005-2022) were proved to be correct except in 2015, the IMD said.

“The six predictors of monsoon onset used in the models are: i) Minimum Temperatures over Northwest India ii) Pre-monsoon rainfall peak over the south Peninsula iii) Outgoing Longwave Radiation (OLR) over the South China Sea (iv) Lower tropospheric zonal wind over Southeast Indian Ocean (v) Mean sea level pressure over Subtropical NW Pacific Ocean (vi) Upper tropospheric zonal wind over North East Indian Ocean,” IMD release stated.

The southwest monsoon over the Indian mainland is marked by monsoon onset over Kerala and is an important indicator characterizing the transition from a hot and dry season to a rainy season.

Earlier on Tuesday, India Meteorological Department said that no heatwave conditions are expected in Delhi but temperatures will remain up to 40 degrees Celsius during the next seven days.

While talking to ANI, the Regional Head of IMD Delhi, Kuldeep Srivastava said, “Heatwave conditions in the first half of May were less severe due to Western disturbances that affected parts of northwest India. As the next western disturbance is approaching northwest India, for the next 7 days, we are not expecting heatwave conditions there. But the temperature will be higher, up to 40°C”.

He further mentioned that dust-raising winds are prevailing in the regions of Haryana, South Haryana, Delhi NCR, Western Uttar Pradesh, and North-East Rajasthan.