Rains during the June-September season are likely to be 99% of the long-term average, Deshmukh said in a forecast keenly watched by traders and policymakers.
The state-run India Meteorological Department (IMD) considers rains between 96-104% of a 50-year average of 89 centimetres in the entire four-month season as normal. The last time there was a drought with rains below this range was 2009 and before that, in 2004.
India will give its final monsoon forecast in June, IMD chief Ajit Tyagi said.
Monsoon rains, vital for agricultural output and economic growth, irrigate about 60% of farms in the world's second-biggest producer of rice, wheat, sugar and cotton. The farm sector accounts for about 15% of India's nearly $2 trillion economy.
Monsoon is likely to have average rainfall in 2012 despite fears the El Nino weather pattern may emerge in the second half of the season, the IMD chief said last week.
The latest government forecast is also in line with last week's estimate of a global weather forum.
In 2009, the El Nino weather pattern turned monsoon rains patchy, leading to the worst drought in nearly four decades. Rains were within long-term averages in following years, helped by La Nina.
El Nino, an abnormal warming of waters in the equatorial tropical Pacific, is linked with poor rains or a drought-like situation in southeast Asia and Australia.
The La Nina weather pattern, which is associated with heavy rains in south Asia and flooding in the Asia-Pacific region and South America, and drought in Africa, ended in March.
In the interim before El Nino appears, weather officials say a neutral condition continues over the tropical Pacific.