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.

Head to Head - Climate change: Fact or fiction?

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.

Pre-monsoon

There is rain ahead of the monsoon season and in March, April and May most states recorded at least their average rainfall.

However, Orissa and the western states were deficient, with Konkan and Goa at only 14 per cent of normal.

These months are, however, a relatively dry period and characterised this year, as last, by at least one heatwave.

Many states suffered extreme pre-monsoon heat, notably Orissa, Chhattisgarh and Madhya Pradesh. It is now back to normal in these states.

West Rajasthan, on the other hand, is still under heatwave conditions: Bikaner measured 48C on Tuesday and 47C on Wednesday.

The India Meteorological Department has maintained a heatwave warning for West Rajasthan until Friday and a watch level beyond that.

Sunitha Devi, the India Meteorological Department's Pune director, told the Indian Express that "the southwest monsoon seems to be at a normal pace and even as there was a slight delay of one week, it should cover the country well within the period announced as of July 15".

The forecast rainfall amounts for this monsoon season remain above average across all of India, but not by much: it stands at between 102 and 110 percent of the long-term average.

Source: Al Jazeera