During the month, rainfall activity would largely remain confined to west coast, northeast India and the southern peninsula, the Indian Institute of Tropical Meteorology, Pune said.
"Large-scale forecast suggests that the monsoon will remain over peninsular India up to June 25 and may advance to central India afterwards," the IITM said, blaming an anti- cyclonic circulation over central India for the delay in advancement of monsoon.
Indian Meteorological Department had earlier said the monsoon is expected to be below normal at about 95 per cent because of El-Nino effect, which is generally associated with the warming of ocean water.
IMD Director General L S Rathore said there was "sluggish march" in the onset phase while announcing the arrival of Monsoon.
Met department had predicted that it will hit Kerala on June 5 instead of June 1.
The sluggish pace of the monsoon could dampen the spirit of farmers as the agriculture sector in the country is largely rain-fed. The country has seen normal and above-normal monsoon during the last four years.
A senior IMD official also said that weak monsoon could also mean "patchy rains", a phenomenon that includes rains in some parts of the country and deficient rain in other parts.