There are fears of drought if the rains are patchy
Indian officials say that monsoon rains in the country are likely to be "below normal" triggering off fears about crop failure and high food prices.
Forecasters say that rainfall is likely to be lower than predicted in April, when they said it would be near normal.
The government says there is no need for panic, and that heavy rains in July are likely to avert a drought.
A heat wave is sweeping the country and rains are delayed in many parts. Rains usually last from June to September.
"It [the monsoon] is late," federal minister Prithviraj Chavan told reporters.
North-west India appeared to be worst affected by the slow rains with only 81% rains forecast.
Monsoon rains are critical to India's farm prospects, which account for a sixth of economic output.
Up to 70% of Indians are dependent on farm incomes, and about 60% of India's farms depend on rains. Irrigation networks are dismissed by critics as inadequate.
The summer rains are crucial to crops such as rice, soybean, sugarcane and cotton.
The Indian media has been full of reports about the patchy rains so far.
A heat wave is scorching the country
"Praying for rain, bracing for worst" headlined the Hindustan Times on its front page on Wednesday.
The newspaper said that in at least eight states, monsoon rains so far had been 60 to 90% below normal.
"There is concern but no worry as yet. There is still time," Farm Secretary T Nanda Kumar told the newspaper.
One analyst said delay in the rains in some parts of India could hit economic growth.
"Delay in monsoon will play the spoilsport and may hit GDP by at least 1 to 1.5 percentage points," stockbroker VK Sharma, told the Reuters news agency.
Economists agree that the delay will cause further stress in a country where food prices are already high.
"The delay is not a good signal. Food prices are already high and any delay could push food prices higher. Food price inflation could emerge as a concern," said DK Joshi, principal economist at credit ratings agency Crisil.
Politicians in many states are holding special prayers for the rains - the farm minister in central Chhattisgarh state held a prayer for the state to get rains soon.