The weather office had already forecast an average monsoon in April, before the rainy season started, although with slightly heavier rains.
The meteorological department said in a statement that monsoon rains in 2012 would be 96 per cent of the long-term average overall, down from its April forecast of 99 per cent.
A normal or average monsoon means rainfall between 96-104 per cent of a 50-year average of 89 cm in total during the four-month season from June, according to India's weather office classification.
The monsoon rains are crucial for farm output and economic growth as about 55 per cent of the south Asian nation's arable land is rain-fed, and the farm sector accounts for about 15 per cent of a nearly $2 trillion economy, Asia's third-biggest.
The weather office also forecast average rains in July and August, key months for planting and maturing of crops.
July rains this year are likely to be 98 per cent of the long period average, while the rainfall in August is forecast to be 96 per cent of the average.
Rains picked up from early lows last week, but concerns remain as the monsoon is still performing below average and the rains are behind schedule particularly in the grain bowl of the north-west.
"The latest forecast is good and definitely not alarming as the long term average has not been revised below 90 per cent which would have meant a drought this year," M. Rajeevan, senior scientist at the ministry of earth sciences, said.
Average rainfall this year would mean avoiding a drought for a third year in a row in one of the world's biggest consumers of rice, wheat and sugar, with a population of about 1.2 billion.
India is also one of the largest producers of rice, wheat, sugar and cotton.
Rainfall below 90 per cent of the average is considered as a drought, and comes under the deficit category of the weather office. The last time there was a drought with rains below this range was 2009 and before that, in 2004.
Rainfall between 90 to 96 per cent of average is considered below average while above 110 per cent of the average would mean an excessive monsoon—not as damaging as drought but potentially hurting yields of sugar cane.
Copyright: Thomson Reuters 2012