The onset of monsoon over Kerala is likely to be slightly delayed this year with the IMD predicting its arrival on June 4, three days after the normal date (June 1).
However, the monsoon's delayed arrival on the Indian subcontinent has little to do with its future development or its quantitative/spatial distribution. Although the monsoon arrived in Kerala seven days later than usual in 2019, the year saw "above normal" rainfall.
Despite growing El Nino conditions (extraordinary warming of the surface waters in the eastern Pacific Ocean), which is typically associated with weak monsoon rains, the IMD had anticipated quantitatively "normal" monsoon precipitation this year on April 11.
Making its onset forecast for this year, the weather office said, “This year, the southwest (summer) monsoon onset over Kerala is likely to be slightly delayed than the normal date. The monsoon onset over Kerala is likely to be on June 4 with a model error of ± 4 days. ”
June 1 is considered the normal date with a standard deviation of about 7 days. It marks the arrival of the four-month rainy season (June-September) in India even as it arrives over Andaman & Nicobar Islands much earlier. “Southwest monsoon is very likely to advance into some parts of South Bay of Bengal, South Andaman Sea and Nicobar islands during the next 2-3 days,” said senior IMD scientist R K Jenamani.