NEW DELHI: The southwest monsoon reached Kerala on Saturday, marking its earliest onset over the Indian mainland since 2009, according to the India Meteorological Department (IMD). In 2009, the monsoon arrived on 23 May, while the earliest ever recorded onset was on 18 May in 1990.
Heavy rains lashed across the state, especially in the northern districts and major damages were from different parts of the state including uprooting of trees, falling billboards, snapping of power lines and water logging.
The Meteorological Department also predicted squally weather with wind speed 35 kmph to 45 kmph gusting to 55 kmph along the Kerala coast and fishermen were advised not to venture out into the sea.
The IMD had already forecast an early onset of the southwest monsoon (SWM) with above-normal rainfall across the country for 2025. On 10 May, the IMD had predicted the monsoon’s arrival over the Kerala coast by 27 May.
In its initial monsoon forecast released on 15 April, the IMD projected a high probability of above-normal seasonal rainfall throughout the country. It expects the 2025 southwest monsoon to exceed 105% of the long-period average (LPA), with a model error margin of ±5%.
The IMD has indicated an 89% overall probability of normal to above-normal monsoon rainfall. There is a strong 59% probability of above-normal rainfall, a 30% chance of normal rainfall, and only an 11% likelihood of below-normal or deficient monsoon rainfall. The LPA for seasonal rainfall from June to September, based on data from 1971 to 2020, is 87 cm (870 mm).
India’s private weather forecasting agency, Skymet, has also predicted a normal monsoon for 2025, estimating rainfall at 103% of the LPA.
Meanwhile, a low-pressure system over the east-central Arabian Sea and the south Konkan coast has intensified into a depression. According to the latest IMD bulletin, it is moving eastward at a speed of 6 km/h and is expected to cross the south Konkan coast between Ratnagiri and Dapoli by noon on 24 May 2025.
Typically, the southwest monsoon sets in over Kerala around 1 June and covers the entire country by 8 July. It begins to retreat from northwest India around 17 September and withdraws completely by 15 October.
According to IMD data, the monsoon’s onset over Kerala in previous years was as follows: 30 May in 2024; 8 June in 2023; 29 May in 2022; 3 June in 2021; 1 June in 2020; 8 June in 2019; and 29 May in 2018.
Meteorologists have reiterated that there is no direct correlation between the onset date of the monsoon and the total rainfall received across the country during the season.
“The monsoon’s arrival in Kerala, whether early or late, does not necessarily indicate how it will progress across the rest of India,” an IMD official explained, noting that the monsoon is shaped by large-scale variabilities, as well as global, regional, and local climatic factors.
In its April forecast, the IMD had ruled out the possibility of El Niño conditions commonly linked with below-normal rainfall in the Indian subcontinent strengthening optimism for a healthy monsoon season this year.
(With inputs from PTI)
