Heatwave and hotspots increase across India

Heatwaves (HWs) in India have intensified significantly over the past two decades, with projections of further increase in frequency and duration, according to a recent study published in the journal ‘Scientific Reports’.

The Introduction to the study says that global temperatures have increased since the industrial era, and a corresponding increase in the incidence of extreme heatwave (HW) events is occurring worldwide. Summertime episodes with extremely high surface air temperatures lasting for several days are often referred to as HWs. Projections indicate a concerning rise in intensity, frequency, and duration of HWs, which is expected to amplify their detrimental effects, especially in the most vulnerable regions. South Asia is among the most vulnerable regions to climate extremes, with many areas already experiencing extreme heat stress.

The study, titled ‘Intensification and spatial shifts of heatwave hotspot across India under climate and ENSO influences with health risk assessment’ adds that a review of HWs across South Asian countries reveals that the region has documented some of the warmest temperatures ever recorded. Notably, from 2015 to 2025, each year ranked among the 10 warmest years on record, with the trend worsening yearly. India has the longest record of data in South Asia, and reports indicate that the frequency of hot days and hot nights has increased since 1960. From 1970 to 2019, India experienced over 706 HWs, with the number increasing from approximately 3 HWs per year in the 1970s to around 25 per year in the 2010s and 2020s. HWs in India have increased in frequency, total duration, and maximum duration, with significant changes in their spatial extent compared to the base period 1950–1980. The frequency and intensity of HWs in India are projected to increase in the future.

The study also found, says an analysis of the study by The Wire, that the extent of heat hotspots in the country has increased during these years by 1.5 times. Parts of western India, the southeastern coast and the Indo-Gangetic Plain are among the areas most at risk in terms of health impacts on people. Recent research predicts that deaths caused by intense heat are likely to increase in the country too. In March, a global report predicted that with current levels of warming caused by climate change, parts of northwestern and central India could witness as many as 24 deaths per every 100,000 people due to hotter temperatures.

Trends in daily maximum temperatures are one way to assess changes over years, The Wire analysis adds. A team of scientists from the Indian Institute of Tropical Meteorology Pune and the National Remote Sensing Centre Hyderabad analysed the daily maximum temperatures for the two hottest months in India – April and May – from 1981 to 2020. They found that the average daily maximum temperature increased by ~0.5°C by 2000, and by ~1.0°C by 2020 when compared to 1981 levels due to human-caused warming (activities such as the use of fossil fuels that release carbon emissions into the atmosphere which in turn traps greenhouse gases that increase temperatures globally). North-western and central India and the coast of Andhra Pradesh experienced the most significant increases. The team also found that average daily maximum temperatures are steadily rising in southern India.

Moreover, India’s weather office has forecast a below-average monsoon in 2026, with an El Nino expected to develop and weigh on rainfall in the latter half of the June to September season, according to a Reuters report. In the past, India has seen below-average rainfall in most El Nino years, at times triggering severe droughts that ravaged crops and prompted export curbs on certain grains. While El Nino is strongly linked to weaker monsoons, India has still seen average or above-average rains in at least five of 17 such events over the past seven decades. However, in the last six El Nino years, India has received below-average rains. The Reuters report adds that below-normal rainfall could mean smaller harvests of crops such as rice, cotton and soybeans, while also weighing on winter crops like wheat and rapeseed due to lower soil moisture. A weaker monsoon could also hit power generation by reducing ⁠hydropower output, which accounts for about 6% of the mix.