India’s pre-monsoon season this year has taken an unusual turn, with widespread and intense rainfall recorded across multiple regions, even as heatwaves continue to grip parts of the country. A detailed analysis highlights that the unexpected surge in rainfall during March and April 2026 is closely linked to the combined influence of powerful anti-cyclonic systems and an unusually high number of active weather disturbances.
According to data from the India Meteorological Department, weather patterns throughout March were marked by a mix of heatwaves, thunderstorms, hailstorms and significant rainfall events. While such variability is not uncommon during the pre-monsoon phase, the scale and frequency observed this year have raised scientific interest and concern.
Meteorologists point to two quasi-permanent anti-cyclones one over the Bay of Bengal and another over the Arabian Sea as key drivers behind the excess rainfall. These high-pressure systems developed earlier than usual and played a crucial role in transporting large volumes of moisture toward the Indian subcontinent. This moisture, when combined with active weather systems over land, resulted in frequent and intense rainfall episodes.
Climate scientist K J Ramesh explained that rising temperatures during late February and early March often 3 to 5 degrees Celsius above normal and occasionally as high as 8 to 12 degrees above average created ideal conditions for thunderstorm formation. As the atmosphere warms, its ability to hold moisture increases significantly, leading to heavier rainfall when triggered by weather disturbances.
March alone witnessed heavy rainfall of 7 to 11 centimetres in at least one part of the country on nearly 20 days. As many as 18 states and two Union Territories recorded heavy to very heavy rainfall during the month. The northeastern region, which had experienced rainfall deficits in previous seasons, saw a dramatic reversal. States such as Nagaland and Assam recorded excess rainfall of 131 per cent and 129 per cent respectively, while even regions like Arunachal Pradesh reported above-average precipitation.
Eastern states including Odisha, West Bengal and Bihar also experienced intense rainfall events, with West Bengal recording an extraordinary 231 per cent excess rainfall and Bihar 215 per cent. In southern India, states like Karnataka saw rainfall levels exceeding normal by 136 per cent, while western and northern regions such as Gujarat, Jammu and Kashmir and Uttarakhand also witnessed heavy showers.
A major contributing factor was the persistent activity of western disturbances weather systems originating outside India that influence rainfall and temperature patterns. In March, at least one western disturbance was active on 27 days, with a total of eight such systems recorded. These were accompanied by cyclonic circulations, low-pressure troughs and strong wind systems, creating a highly dynamic and unstable atmosphere across the country.
The interaction between these disturbances and the moisture-laden winds from surrounding seas intensified rainfall events. As western disturbances moved from regions like Iran and Afghanistan toward Pakistan and northwest India, they tapped into moisture from both the Arabian Sea and the Bay of Bengal, further strengthening storm systems.
April continued to witness similar patterns, although with slightly reduced rainfall intensity compared to March. Thunderstorms remained the most frequent extreme weather event, often accompanied by hailstorms. At the same time, rising temperatures began to reassert themselves in parts of northwest and eastern India.
Experts note that the concept of “moisture loading” where atmospheric systems accumulate and transport higher levels of water vapour has become more pronounced this season. This is largely driven by above-normal warming, which enhances evaporation and increases the atmosphere’s moisture-holding capacity.
The evolving weather scenario underscores the growing complexity of India’s climate system, where extreme heat and heavy rainfall are increasingly occurring side by side. Scientists warn that such patterns may become more frequent in the future, highlighting the urgent need for better preparedness and adaptive strategies to manage the impacts of climate variability.