Monsoon Arrives Early in Kerala, Earliest Onset Since 2009: IMD

The southwest monsoon arrived early over Kerala on Saturday, the earliest to make landfall in the Indian mainland after May 23, 2009, according to a report by the India Meteorological Department (IMD).

The southwest monsoon normally reaches Kerala by June 1 and then spreads slowly over the whole country by about July 8. It normally starts retreating from northwest India by September 17, with complete withdrawal by October 15.

IMD records indicate that in recent years, the monsoon has come on May 30 in Kerala in 2022; June 8 in 2023; May 29 in 2022; June 3 in 2021; June 1 in 2020; June 8 in 2019; and May 29 in 2018.

Historical data since 1975 show that the first monsoon arrival over Kerala was in 1990, when it appeared on May 19—13 days before the normal date.

Meteorologists are stressing that the arrival time of the monsoon in Kerala has no direct relationship with the country's total rainfall that it witnesses during the season. The date of onset over Kerala is not a sure measure of the way the monsoon will unfold over the rest of India, which depends on a multifaceted combination of global, regional, and local factors.

Its April forecast put out in the calendar month projected an above-normal cumulative rainfall for the 2025 monsoon, ruling out the chances of El Niño conditions, which are generally associated with decreased rainfall over the Indian subcontinent.

On IMD scales, rain of 96% to 104% of the long-term average of 50 years, i.e., 87 cm—is 'normal.' Less than 90% of this long-term average is 'deficient'; 90% to 95% is 'below normal'; 105% to 110% is 'above normal'; and anything more than 110% is 'excess.'

India had 934.8 mm of rainfall in 2024, which was 108% of the average and a record high after 2020. The nation saw 820 mm in 2023 (94.4% of average), 925 mm in 2022, 870 mm in 2021, and 958 mm in 2020, based on IMD data.

The southwest monsoon is crucial for the agriculture of India, which sustains almost 42% of the country's population and generates 18.2% of the country's GDP. The monsoon is also crucial for replenishing reservoirs, which supply drinking water and produce electricity in the country.