The southwest monsoon hit India on Thursday with its onset over Kerala, a week later than normal, the India Meteorological Department (IMD) announced.

Meteorologists earlier said Cyclone 'Biparjoy' had been impacting the intensity of the monsoon and that its onset over Kerala would be "mild".

In a statement on Thursday, the IMD said, "The southwest monsoon has set in over Kerala today, June 8."

"The monsoon has advanced into remaining parts of south Arabian Sea and some parts of central Arabian Sea, entire Lakshadweep area, most parts of Kerala, most parts of south Tamil Nadu, remaining parts of Comorin area, Gulf of Mannar and some more parts of southwest, central and northeast Bay of Bengal today," it added.

The southwest monsoon normally sets in over Kerala on June 1 with a standard deviation of about seven days. In mid-May, the IMD said the monsoon might arrive in Kerala by June 4.

Skymet had predicted the monsoon onset over Kerala on June 7, with an error margin of three days.

Over the last 150 years, the date of the monsoon onset over Kerala has varied widely, the earliest being May 11 in 1918 and the most delayed being June 18 in 1972, according to IMD data.

The southwest monsoon arrived in the southern state on May 29 last year, June 3 in 2021, June 1 in 2020, June 8 in 2019 and May 29 in 2018.

Research shows a delay in the monsoon onset over Kerala (MOK) does not necessarily mean a delay in the monsoon onset over northwest India.

However, a delay in the MOK is generally associated with a delay in onset at least over the southern states and Mumbai.

Scientists say a delayed MOK also does not impact the total rainfall over the country during the season.

India is expected to get normal rainfall during the southwest monsoon season despite the evolving El Nino conditions, the IMD had earlier said.

Northwest India is expected to see normal to below-normal rainfall. East and northeast, central, and south peninsula are expected to receive normal rainfall at 94-106 per cent of the long-period average.

Rainfall less than 90 per cent of the long-period average is considered 'deficient', between 90 per cent and 95 per cent is 'below normal', between 105 per cent and 110 per cent is 'above normal' and more than 100 per cent is 'excess' precipitation.

Normal rainfall is critical for India's agricultural landscape, with 52 per cent of the net cultivated area relying on it. It is also crucial for replenishing reservoirs critical for drinking water, apart from power generation across the country.

Rainfed agriculture accounts for about 40 per cent of the country's total food production, making it a crucial contributor to India's food security and economic stability.