Bengaluru : In a significant development, the India Meteorological Department (IMD) has forecast that the southwest monsoon is likely to make an early onset over Kerala on May 27, five days ahead of the normal date of June 1. If the forecast holds true, it will be the earliest onset since 2009, when the monsoon arrived on May 23.

“The conditions are becoming favourable for the onset of monsoon over Kerala around May 27,” the IMD said on Monday. A timely and strong monsoon onset is considered crucial for agricultural planning, water reservoir replenishment, and early sowing in rain-fed regions.

Earlier Onsets Rare

The average monsoon onset date over Kerala is June 1, with a standard deviation of about ±7 days. However, such early arrivals are rare. In the last 15 years, only two instances of May arrivals have been recorded: in 2009 (May 23) and 2018 (May 29).

Recent monsoon onset dates over Kerala:

2023: May 30

2022: June 8

2021: June 3

2020: June 1

2019: June 8

2018: May 29

What Happens After Onset?

Once the monsoon sets over Kerala, it typically covers the entire Indian mainland by around July 8, progressing northward in phases. It begins to retreat from north-western India around September 17, and usually withdraws fully by October 15.

While the onset date garners attention, experts caution that it does not determine the overall monsoon performance across the country. “An early or late onset over Kerala does not necessarily mean similar behaviour elsewhere. The spread, intensity, and duration of the monsoon depend on several global and regional climatic factors,” an IMD official noted.

Above-Average Monsoon Expected in 2024

In a related development, the Ministry of Earth Sciences has projected above-normal rainfall for the four-month monsoon season (June–September) in 2024. Secretary M. Ravichandran said India is unlikely to experience El Niño conditions — which are typically associated with deficient rainfall.

The country is expected to receive 105% of the Long Period Average (LPA) rainfall this year. The LPA for India, based on 50-year data, stands at 87 cm. Rainfall in the range of 96–104% of LPA is considered normal, while 105–110% is classified as above normal. Anything beyond 110% is termed excess rainfall.

Why It Matters: Agriculture and Economy

The monsoon is the lifeline of Indian agriculture, which employs over 42% of the population and contributes nearly 18.2% to India’s GDP. A strong start and steady spread of the monsoon are critical for the timely sowing of kharif crops such as rice, pulses, and oilseeds, especially in rain-fed regions with little or no irrigation. (eom)