Heatwaves hit India sooner than expected in 2025. Scientists reveal the alarming reason

India is witnessing a heatwave season early this year with west coast temperatures soaring this week, a report said on February 27. The early arrival of heatwave is being attributed to an extremely rain-deficient winter season, among other reasons. 

The west coast has been experiencing hot and humid weather conditions, especially in parts of coastal Maharashtra and Goa. The India Meteorological Department (IMD) issued a heatwave warning for the coastal city of Mumbai for February 25 and 26. On February 26, Mumbai recorded a maximum temperature of 38.7°C, which was 5.9 degrees above the normal average, said the report compiled by Climate Trends, a research-based consultancy firm on environment and climate change. 

Some other regions in Coastal Maharashtra and Goa have also reported heatwaves, with the mercury soaring beyond 37 degrees °C. Coastal parts of Karnataka and Gujarat also witnessed hot and sultry weather conditions, with temperatures just short of ticking the threshold of heatwave and settling in the range of 35°C to 37°C.

Heatwaves typically occur between March and June, and in some rare cases even extend till July. The criteria for declaring heatwave for coastal stations in India is when the maximum temperature departure is 4.5°C or more.

IMD, the country’s nodal weather agency, has predicted that hot and humid weather conditions will persist over the next couple of days, even if the heatwave recedes.

According to meteorologists, the ongoing hot and humid weather results from an extremely rain-deficient winter.

“It would not be wrong if we say that this year, the country has been witnessing one of the most dry winter seasons. In the absence of any weather systems, rains have remained in hiding. An anti-cyclone has been persisting over Madhya Pradesh, which had been pushing warm easterly winds across the west Coast. These inland winds delayed the setting of sea breezes, and prolonged land breezes led to a rise in mercury,” Mahesh Palawat, VP of meteorology and climate change at Skymet Weather was quoted as saying in a report.

“Besides this, high humidity levels due to the proximity of the coast increased the discomfort manifold, resulting in heatwave-like conditions,” he said

During the day, when the land heats up more quickly than the water, cooler air from the sea (sea breeze) moves inland to restore balance. Similarly, due to the high specific heat of water, the sea takes longer to cool after sunset. At night, cooler air from the land (land breeze) flows toward the sea, helping to maintain equilibrium.

‘Human-caused climate change’

According to the Climate Shift Index (CSI) by US-based weather agency Climate Central, the last three day temperatures (Feb 25-27) in Panaji, Goa were made at least five times more likely by human-caused climate change. Similarly, temperatures in Mumbai during the same time frame were at least 3 times more likely due to global warming.

CSI is a system that quantifies the influence of climate change on local daily temperatures around the world. The CSI ranges from -5 to +5. Positive levels indicate temperatures that are becoming more likely due to climate change (negative scores indicate conditions that are becoming less likely).

“Anthropogenic climate change is escalating both meteorological and hydrological extremes worldwide, resulting in frequent weather record-breaking events. Currently, warmer-than-usual temperatures are being observed across all continents, indicating a relatively uniform global warming pattern. Unless we limit global warming by rapidly cutting the emission of greenhouse gases, weather records will continue to break frequently,” said Dr Akshay Deoras, Research Scientist, National Centre for Atmospheric Science and the Department of Meteorology, University of Reading, UK.

India witnessed an intense and prolonged heatwave season in 2024, also making it the hottest year on record. As per the data given by IMD, the country witnessed 536 heatwave days during the summer of 2024. This has been the highest since 2010, when we registered 578 heatwave days.

May, the peak heatwave month, recorded the fourth-highest mean temperature in 2024 since 1901. Northwest India was worst affected, with the third highest maximum ever with an anomaly of 1.81 Degrees Celsius during the month.