The Indian monsoon has arrived on the mainland

The seasonal rains are a week late but are still forecast to be better than average.

Vehicles wade through water logged road after a rain shower in Mumbai, India, 07 June 2012. According to Indian Meteorological Department (IMD), monsoon hit the north-east India on 06 June 2012, expecting it to advance quickly in the coming days to other parts of the country.

It rained in Kerala on Wednesday as 112mm was recorded in Thiruvananthapuram in the south and 90mm in Kannur in the north.

In the two preceding days, the 14 designated rainfall stations in Kerala were wet; the wind over the southern Arabian Sea was a westerly from the sea surface up to 5,000m; the wind at 600m above land blew at about 30km per hour (kph); and the sunshine received on land was below 200 watts per square metre - in other words, it was cloudy.

These same criteria must be met every year before the arrival of the monsoon rains can be announced.
This consistency allows a long climatological record to be kept and useful comparisons can be made for all of India.

This year, the Indian Meteorological Department declared on Wednesday that the southwest monsoon had arrived in Kerala. The monsoon, which marks the beginning of the rainy season in the country, is crucial for India’s farmers, especially with several states grappling with drought-like conditions.

Every year, the forecast strength, and onset date, of the monsoon rains is a matter of national importance and international interest.

This is because 58 per cent of India's population is currently sustained through near subsistence agriculture.
More than 70 per cent of rural households depend on agriculture as their principal means of livelihood.
Agriculture, along with fisheries and forestry, accounts for one-third of the nation’s GDP and is its single largest contributor.