(Image source from: Newindianexpress.com)
The southwest monsoon arrived in Kerala on Saturday, marking the earliest onset over the Indian mainland since 2009, when it first reached this southern region on May 23, according to the India Meteorological Department (IMD). Typically, the southwest monsoon begins its journey in Kerala by June 1 and extends across the entire country by July 8. It usually retreats from northwest India around September 17 and is completely gone by October 15. The onset dates over Kerala in previous years have been as follows: May 30 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, as per IMD records. Historical data since 1975 indicates that the earliest arrival was in 1990, occurring on May 19, which is 13 days earlier than the typical date. Meteorologists have noted that there is no direct correlation between when the monsoon begins and the total seasonal rainfall experienced across the country.
The early or late arrival of the monsoon in Kerala does not influence its timing in other regions. The monsoon exhibits considerable variability and is affected by an array of global, regional, and local factors, according to an IMD official. In April, the IMD predicted above-normal cumulative rainfall for the monsoon season of 2025, stating that El Nino conditions—typically linked with below-average rainfall in India—will not be a factor this year. The IMD defines normal rainfall as being between 96 percent and 104 percent of the 50-year average of 87 cm. Conversely, rainfall measured at less than 90 percent of the long-term average is categorized as deficient; those between 90 percent and 95 percent are labeled below normal; while amounts from 105 percent to 110 percent are considered above normal, and figures exceeding 110 percent are recognized as excessive rain.
In 2024, India experienced 934.8 mm of rainfall, making it 108 percent of the average and the highest recorded since 2020. The year 2023 saw 820 mm, or 94.4 percent of the average. Past rainfall amounts included 925 mm in 2022, 870 mm in 2021, and 958 mm in 2020, according to the IMD. The monsoon plays a vital role in India’s agricultural sector, which is crucial for the livelihoods of about 42 percent of the population and contributes 18.2 percent to the nation’s GDP. Additionally, it is important for replenishing reservoirs essential for drinking water and electricity generation nationwide.
