Heatwaves Across India: This Year Expected to Be Hottest Yet, Warn Experts

"In the last two years, heatwaves are occurring sooner and sooner," say experts.

On Sunday, 20 April, Delhi recorded its highest minimum temperature in three years. Since then, a severe heatwave has swept across northwestern India, with temperatures soaring above 40°C in Delhi-NCR, Odisha, Telangana, Haryana, Punjab, Madhya Pradesh, and Uttar Pradesh, according to the India Meteorological Department (IMD).

(Photo: PTI/Altered by The Quint)

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"It feels like the peak of summer. The fan already feels inadequate," said Dilip, a 31-year-old based in Bengaluru, back in March.

Dilip is employed as a domestic worker in four houses in the city. His day starts before the sun is fully up to try and beat the heat. "I wake up at 4:30 AM so that I can get some of my own household work done before I leave for work. By 8 AM, it’s already too hot, and I'm sweating profusely," he stated.

Dilip, originally from Nepal, has been living in Bengaluru for over 10 years. He reminisces about a time when the city was known for its mild, temperate weather year-round. "Gone are those days," he added. "I worry about how I will manage without a cooler now, which is something I can't afford. It's getting very difficult."

What Dilip is experiencing isn't unique. Millions of people in different parts of India can relate to right now.

On Sunday, 20 April, Delhi recorded its highest minimum temperature in three years. Since then, a severe heatwave has swept across northwestern India, with temperatures soaring above 40°C in Delhi-NCR, Odisha, Telangana, Haryana, Punjab, Madhya Pradesh, and Uttar Pradesh, according to the India Meteorological Department (IMD).

But the precedent for this upcoming summer was set very early in the year.

On 25 February, Goa recorded India’s first heatwave of 2025 — well ahead of schedule. This was also the first heatwave recorded during the winter season. Since then, several regions across the country, including coastal Telangana, Odisha, Maharashtra, and now Delhi, have experienced and continue to experience heatwave conditions.

Key points of heatwave conditions in India so far.

(Photo: The Quint)

Key points of heatwave conditions in India so far.

(Photo: The Quint)

• Delhi recorded a maximum temperature of 40.5°C on 26 March, 6.3°C above the normal for this time of year.

• Odisha recorded India's highest temperature on 15 March, reaching 42.5°C.

• Jharkhand experienced its first warm night of the year on 15 March, much earlier than in 2024 (which occurred in May).

• Karnataka experienced an unusually hot summer starting in February, with temperatures reaching 40.1°C between 28 February and 1 March. In mid-March, Bengaluru was hotter than both Delhi and Mumbai.

• Telangana recorded above-normal temperatures in March, with the first heatwave alert issued by the Hyderabad Meteorological Department on 2 March.

• Jammu and Kashmir recorded night temperatures 5.1°C above normal between 11 and 23 February.

• In Maharashtra, heatstroke cases surged fivefold in two weeks, rising from 4 March on 8 March to 23 March by 25 March. Eight districts in Vidarbha recorded temperatures exceeding 40°C on 26 March.

"We don’t generally expect heatwaves happening in March. But since the last two years, we have been seeing that heatwaves are occurring sooner and sooner," Dr M Rajeevan, climate scientist and former secretary of the Ministry of Earth Sciences (MoES), tells The Quint.

He adds,

"There is a clear pattern of steady increase of heatwaves – frequency, duration and intensity."

Brace Yourself for the Summer

Dr Rajeevan, who has worked with the IMD for over 25 years, says, "We can now predict heatwaves up to a week in advance. We can predict where the heatwaves are going to occur, when they will happen, and how intense they will be."

This, he explains, is based on mathematical models that are also used for general weather forecasts.

Using a slightly different climate model, it is also possible to make seasonal forecasts.

According to the IMD's Seasonal Heat Outlook report for March to May, most parts of the country are predicted to experience above-normal maximum temperatures in the upcoming hot weather season (March to May) (MAM).

Probability forecast of Maximum Temperature for March to May 2025.

(Source: IMD)

Anomaly (Deviation from the normal) of Heat Wave Duration (days) for March 2025 to May 2025.

(Source: IMD)

"During March to May season 2025, above normal number of heatwave days are likely over most parts of the country except over Northeast India, extreme north India and southwestern and southern parts of Peninsular India."

India Meteorological Department

“We have been seeing a trend in recent years that the summer's coming early," Aditya Pillai, researcher at the Sustainable Futures Collaborative and expert on heat resilience and adaptation, tells the Quint. "The change from winter to summer is happening way more rapidly."

"The duration of heat is also getting longer – hot days and hot nights are getting longer," says Abhiyant Tiwari, lead climate resilience and health consultant at NRDC (National Research Development Corporation) India.

He explains that heatwaves in the early parts of summer tend to be more harmful. This is because the transition from winter to summer is a time when the body acclimatises to the change in seasons. "But when this change happens suddenly and there is a sudden spike in temperature, it poses a health risk, particularly to vulnerable groups like children, elderly pregnant women and those with comorbidities like heart conditions," says Tiwari.

"Hot nights are more concerning because nighttime is when the body physiologically cools down and gets relief from the heat. But if nighttime also remains hot, then the overall heat load that people are exposed to puts them at risk."

Abhiyant Tiwari

Past Trends and Future Predictions

While occasional hotter-than-usual summers might be considered outliers, data shows that extreme heat during the summer months has been consistently rising in recent years.

According to data from the World Bank's Climate Change Knowledge Portal, the average minimum and maximum surface temperatures in India have also been slowly, but steadily rising.

Observed Annual Average Maximum Surface Air Temperature of Infia (1901 - 2023)

(Source: World Bank)

This is true not only for India, but across the world, say experts. And as heatwaves spread, it’s clear that the impact will be felt by millions, affecting everything from daily routines to public health and infrastructure.

"The key point to make here is that we are not dealing with something that any of us fully understand," says Pillai.

"A lot of people say this is the new normal, but what needs to be underlined here is ‘new’. None of us in our lifetimes have experienced a climate that has operated like this and changing so rapidly."

Aditya Pillai

This means we also don't yet fully understand the extent of the impact of prolonged harsh summers and a rapidly changing climate.

"Much of how society functions are based on seasonality—what people choose to do for work, when crops are grown, daily schedules, what people eat, and the general quality of day-to-day life. Everything is interconnected and relies on seasonal temperatures. As these patterns change and become more unpredictable as a direct consequence of the planet warming due to climate change, it’s difficult to foresee the full extent of their impact on our lives, because everything is so intricately linked," explains Pillai.

But one thing that we do understand (and all experts agree on) is that global warming, driven by climate change, is a significant and undeniable contributing factor

"Heatwaves are primarily caused by two factors: global warming and certain atmospheric patterns that create conditions favorable for heatwaves."

Dr M Rajeevan, Former Secretary, MoES

"For example, a lack of rain leads to dry soil, which contributes to the intensity of heatwaves. These atmospheric patterns can occur naturally but are also indirectly influenced by human-caused climate change," explains Dr Rajeevan.

Are We Prepared?

A report published earlier this month found that Indian cities most vulnerable to extreme heat are unprepared for worsening heatwaves, relying mainly on short-term emergency measures rather than long-term resilience planning.

According to experts, while short-term measures can help deal with the aftermath of heatwaves, they are only temporary solutions. 'Here you are reacting to the ongoing heatwave, and there’s only so much you can do,' says Tiwari.

Long-term risk management involves implementing structural changes to prepare for and mitigate the risk of extreme heat before it strikes.

"If heatwaves are arriving earlier and lasting longer, then the planning cycles in cities will have to change as well. They will have to be prepared earlier," says Pillai.

The first step must be awareness, adds Tiwari. "People should understand the seriousness of extreme heat conditions and know when extreme heat spells are approaching, and what precautions they should take. Keep up to date with advisories issued by the state and central governments and various health authorities."