India is likely to receive below-average rainfall in August due to the El Nino weather pattern, a senior weather department official said on Monday, after an above-average monsoon in July helped farmers accelerate crop planting.

The monsoon, vital for India's US$3 trillion (about RM13.5 trillion) economy, delivers nearly 70% of the rain needed to water its farms and refill reservoirs and aquifers.

Rainfall in August is estimated at 92% of the long-period average, Mrutyunjay Mohapatra, director-general of the India Meteorological Department (IMD), told a virtual press conference.

Farmers typically start planting rice, corn, cotton, soybeans, sugarcane and peanuts, among other crops, from June 1, when monsoon rains are expected to begin drenching India. Sowing usually lasts until July and early August.

Summer rains are crucial as nearly half of India's farmland lacks irrigation.

Rice growing states in eastern India could receive surplus rainfall in August, while rainfall in rice, cotton and sugar cane growing southern states could be below normal, Mohapatra said.

"Sowing of summer crops was delayed due to scant rainfall in June. The crops are not big enough to adjust to stress if rainfall falters in August, which could affect their vegetative growth," said a Mumbai-based dealer with a global trade house.

Rainfall in India in June was 9% below average, but in some states, the rainfall deficit was as much as 60% below normal.

July monsoon rains were 13% above average, and between June 1 and July 31, India experienced monsoon rains that were 5% above average.

The July rains helped farmers accelerate rice planting in India, the world's second biggest producer and largest exporter of the grain.

Nonetheless, earlier this month, India ordered a halt to its largest rice export category - a move that will roughly halve shipments.

Supplies of vegetables and staples such as tomatoes have also been squeezed, raising concerns about a jump in retail inflation, which is expected to hit a seven-month high in July.

Despite estimates of lower rainfall next month, the country's cumulative rainfall in August and September - the last two months of the season - could be average, Mohapatra said.

The IMD has forecast an average amount of rainfall for the entire four-month season despite the formation of an El Nino weather pattern.

A strong El Nino, marked by a warming of the surface of the sea in the Pacific Ocean, can cause severe drought in Southeast Asia, India and Australia.