The government's weather office says the current bout of light to moderate rain across many parts of northern and central India, accompanied by heavy winds, aren't pre-monsoon showers.

"These are nothing but summer season thunderstorms, at least in the northern and central parts. Pre-monsoon showers are still a few days away," D P Yadav, director, India Meteorological Department, said.

IMD has predicted the southwest monsoons onset over Kerala's coast will be delayed by six days, while private weather forecasting agency Skymet said this would start from June 1, its normal time. IMD's forecast is with an error of plus or minus four days.

"The rains in north and central India are mostly due to western disturbances but in the south, yes, we can say some pre-monsoon showers have happened," said D S Pai, deputy director general at IMD.