Thiruvananthapuram, June 1 (IANS): The India Meteorological Department (IMD) officials were on Monday closely watching the conditions that spell the arrival of south-west monsoon.

The IMD earlier forecast that the south-west monsoon was likely to set over Kerala on May 30, with a model error of plus or minus four days.

Speaking to IANS, IMD director here K.Santhosh said the announcement about monsoon arrival would be made from New Delhi.

"To declare that the monsoon has arrived in Kerala, the data recorded at the 14 weather stations located at Lakshadweep, Kerala and in Mangalore are being closely monitored," said Santosh.

There are other aspects also to be monitored before one could say monsoon has arrived, he added.

The officials monitor the rain starting May 10. If 60 percent or more of the stations record 2.5 mm of the rain for two days continuously, it meets the criteria that monsoon has arrived.

Another yardstick that the IMD looks at is the strength of the wind.

Cloud movements are also a key indicator for the weathermen when it comes to announcing the monsoon.

The IMD report shows that in the last one decade the operational forecasts were correct.