"Quantitatively, monsoon season rainfall for the country as a whole will be 96 per cent of the long period average," Laxman Singh Rathore, Director General, India Meteorological Department (IMD) said.
In April, the IMD had said the country would receive 99 per cent rains of the long period average (LPA).
A normal monsoon means rainfall between 96-104 per cent of a 50-year average rains during the four-month season from June to September. The LPA has been pegged at 89 cm.
Most parts of the country are expected to receive good rains in July-August, the crucial months for the country's trillion-dollar economy which depends largely on rain-fed agriculture.
Rains in July 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 LPA.
The Northwest region, including Punjab and Haryana, considered to be India's granary states, are expected to receive below normal rains at 93 per cent of the LPA, according to the IMD's update to its monsoon forecast which was issued on Friday.
Monsoon rains arrived four days late over Kerala on June 5 and are yet to pick up steam due to a string of atmospheric storms in the south-east Asian region which had affected the monsoon current.
Rathore said slow progress has been observed in the advance of monsoon and the same conditions could continue for another four to five days.
"Thereafter monsoon is expected to accentuate," he said. On the reasons for slow progress, Rathore said the storms in the Western Pacific ocean, like the most recent 'Talim', affect monsoon circulation.
D Sivananda Pai, India's chief monsoon forecaster, pointed out that it was normal to have two typhoons in the Western Pacific in June, but this year there have been three, which has resulted in slow progress of monsoon.
The country has witnessed 24 per cent deficient rains till today. September may see less rains than normal in most parts of the country under the impact of El Nino, the warming of the Central Pacific ocean.
Sea Surface Temperatures in the Central Pacific were neutral till recently but there have been signs of warming which is expected to increase during the August-September period.
However, since the warming is expected towards the end of the monsoon period, any decrease in rainfall may not affect agriculture.
"El Nino impact is most likely to be felt on September rains," Pai said. Since the onset, the country on the whole has received 73.7 mm rainfall as against the normal of 96.9 mm for the period of June 1-21.
Rainfall below 90 per cent of the LPA is considered as a drought, and comes under the deficit category. In the recent past, 2004 and 2009 were drought years.