After hitting the Kerala coast on 8 June, a week later than usual, the monsoon has advanced steadily into the rest of the southern states, raising the possibility that it may cover the entire country on time despite its delayed arrival.
The India Meteorological Department said it expects the monsoon to advance rapidly and make up for much of the delay, as vast swathes of the country reel under a hotter-than-usual summer on the back of two years of drought that have seen reservoirs dry up and destroy farm incomes.
''We expect rapid progress till central India. The onset was delayed by seven days, but by the time monsoon advances over central India, the delay will have reduced to a few days, and that way, it may reach north and northwest India in time,'' said D S Pai, head of long-range forecasting at the IMD.
With the onset of the monsoon begins the sowing season for summer crops in India, where 44 per cent of the total food production is from rain-fed farms, which also support about 40 per cent of the country's population.
Consequently, the June-September monsoon season, when India receives 80 per cent of its annual rainfall, is crucial to India's rain-fed agricultural economy.
This year, IMD has forecast above-normal rains at 106 per cent of the long-term average.
Meanwhile, the El Nino weather phenomenon, which was one of the main reasons for the failed monsoon last year, has also ended. Meteorological agencies have now predicted the possibility of La Nina, known as the anti-El Nino, later this year. While El Nino is associated with drier monsoons in India, La Nina is associated with heavier rainfall in the country.
As of Friday, the monsoon has covered the remaining parts of Kerala, Tamil Nadu, most parts of coastal Karnataka, some more parts of south interior Karnataka, some parts of Rayalaseema and coastal Andhra Pradesh. In the next 48 hours, it is expected to cover the rest of Karnataka and more parts of Andhra Pradesh, and reach the Konkan region and Goa.
The south-west monsoon reaches the Andaman Sea normally around 20 May, plus or minus one week.
The advance of the monsoon takes place in two directions: First, along the south-east to northwest direction in the Bay of Bengal from mid May to early June and then, along the west coast and adjoining peninsular India in a south to north direction across the entire west coast of India from the end of May to mid-June.
It moves northwards, usually in surges, and covers the entire country around 15 July after reaching the farthest parts of northwest India.
There are three phases: Between 25 May and 9 June is the beginning of the onset phase of the summer monsoon over the Indian subcontinent and the advance over the southern Indian states and some northeastern states.
It is followed by the 10-29 June period of northward advance when it covers central India, east India and north-eastern India. Between 5 and 24 July is the end of the advance over northwest India and the onset over Pakistan.
While these are the normal phases of monsoon advance in India, IMD scientists say it is not possible to accurately forecast the advance of monsoon beyond two to three days. In 2013, the onset was timely and the progression of the monsoon was the fastest in the last 70 years, but 2014 had a delayed onset and a very staggered progress compared to 2013. The progress can depend on conditions such as low pressure systems.
It remains to be seen how this year's monsoon progresses. The withdrawal of the monsoon starts from northwest around 1 September and from extreme south peninsula on 15 October.