India’s heat
Every reading against its published limit. Every gap named.
1 March to 15 July
OUT OF SEASON — the season is shut; this is the record
46.7°C
the hottest reading in this record · Nagpur, Maharashtra · 24 May 2010
Above IMD’s heat wave threshold
IMD: 45°C is a heat wave anywhere, 47°C is severe. Limit broken by -0.3°C.
8 grid points, ECMWF ERA5 / ERA5-Land reanalysis. What counts as heat.
The one that is coming, not the one that came
Air kills more. The river is worse. But heat is the only situation on this site whose death toll more than doubled in a single year — and it is the one nobody can move away from, insulate against, or filter.
A heatwave has no plume, no smell and no photograph. It leaves no damage to survey. It kills indoors, at night, in people who were already ill, and it is recorded as something else.
4 of these 8 cities set their all-time record in 2024. Not spread across thirty-five years. One year.
Who it kills
1,832 people in 2024. It was 804 the year before.
1,832
deaths recorded as heat or sunstroke, 2024
The second largest killer in India’s national table of deaths from forces of nature, after lightning.
+127.9%
in one year
The largest rise of any cause in the table. Heat’s share of all such deaths went from 12.5% to 23.2%.
Counted or measuredModelled
1,832 is what was filed, not what happened. Heat rarely reaches a death certificate. It kills through heart failure, kidney failure and stroke, in people who were already ill. This number is a floor, not an estimate.
Every death from a force of nature, India, 2024
Lightning kills more than everything else combined — 2,825 deaths, and almost never a story. And 1,626 deaths (20.6%) have no named cause at all.
Nobody publishes heat-related hospital admissions, lost work or school days missed in India. Those are the numbers a city needs to plan with, and they do not exist publicly.
What counts as heat
India does not define a heatwave by a temperature. It defines it by a distance from normal — and the temperature it starts from depends on where you are.
A day is a heat wave when the maximum clears its local floor and stands 4.5°C above the normal for that place and date. 6.5°C above makes it severe.
The floor by zone. Applying the plains figure to Chennai would under-count every coastal city on this page.
There is also an absolute rule, with no reference to normal: 45°C anywhere is a heat wave, 47°C is severe.
So the same 41°C afternoon is a heatwave in March and an ordinary day in June. That is the point, not a loophole. A body acclimatised to June heat is not the body that meets it in March.
A departure needs a normal. Each city gets its own, computed from 1991-2020: for every calendar day, the mean maximum over a ±7-day window. About 450 samples per day.
A departure is meaningless against somebody else's normal. Chennai's normal and Jodhpur's are 10 C apart.
Reproducible, not quoted. Because the normal comes from the same archive as the readings, you can recompute every departure on this page from the source. It is not IMD’s published departure and does not claim to be.
IMD declares for a subdivision on two or more stations. These are single grid points, so these are days MEETING the temperature criteria at each location, not IMD declarations.
So every figure here is days meeting IMD’s criteria at this location, never heatwave days declared by IMD. Different quantities. The second is not ours to publish.
And it is modelled. ERA5 reanalysis — a model constrained by observations, not a station thermometer. An IMD station series would outrank this, not confirm it. Reanalysis also smooths extremes hardest at the tail this subject lives in, and contains no urban heat island.
A grid point is not a city. Fourteen grid points are not a country.
Sources. Criteria: India Meteorological Department — heat wave criteria. Readings: Open-Meteo ERA5 archive. Deaths: Accidental Deaths & Suicides in India 2024, Table 1.0 — Number and Share of Accidental Deaths due to Forces of Nature and Other Causes, 2023 & 2024.
Fourteen cities
The desert, the plateau, the Gangetic plain, both coasts and one hill station. Each measured against the threshold for its own zone.
Sorted by the hottest reading each city has recorded since 1991. The tick marks IMD’s severe threshold, 47°C.
4 of 8 set their record in 2024. 6 requested station(s) did not answer and are omitted, not backfilled.
Last season, city by city
The sum of qualifying days across all 14 stations. It is a count of station-days, NOT a national number of heatwave days. 10 station-days across 8 cities, the last completed season.
What is rising
Not the afternoons. The nights.
Five measures, the first eighteen seasons against the last, counted across all 8 cities. The pale bar is cities where it rose, the grey where it did not move, the dark where it fell.
Dry-bulb heat is not the measure that is rising. Humid heat and warm nights are. Across these 14 stations, the number that moves most consistently upward is not the hottest afternoon — it is the number of nights that never fall below 28°C, and the number of days whose apparent temperature clears 45°C. Peak daytime maxima are close to flat at most stations and fall at some.
Counted as cities, not averaged. How many of the 14 stations move each way between the first and second halves of the record. Published as a count of stations rather than a national average, because averaging 14 grid points does not produce a national trend. Why a night that does not cool is the one to watch.
Why the afternoons are the wrong thing to watch
- It is not evidence that heat is not intensifying. Three of the four things that make heat dangerous are not dry-bulb maximum: humidity, night-time recovery, and duration.
- A grid point is not a city, and 14 grid points are not a country.
- IMD's own declarations are made on station data across subdivisions and are a different quantity from this one.
And who is looking
Lighter bars are months inside the season. Peak 78,038 in Jun 2024, floor 5,174 in Feb 2026 — 15.1×. Attention peaks with the season and is gone by August. NCRB publishes the death count the following year, when nobody is looking.
34 items from 22 publishers. Reporting is tagged as reporting; no figure here came from a headline.
Read the 34 most recent items
- ‘The heat took him from me’: India’s death toll rises amid escalating heat crisisThe Guardian · 29 Jul 2026
- India’s Heatwave Is a Warning for the FutureCarnegie Endowment for International Peace · 02 Jun 2026
- One Day Of Extreme Heat Causes 3,400 Excess Deaths Across India, Study EstimatesNDTV · 29 May 2026
- Workers Are Dying in the Heat in IndiaJacobin · 25 Jun 2026
- Extreme heat causes 3,400 excess deaths per day in India - studyEuronews.com · 10 Jun 2026
- 3,400 deaths in a day: India's extreme heat days are deadlier than we imaginedIndia Today · 01 Jun 2026
- India is being left to die in the heatAl Jazeera · 22 May 2026
- Depending on Their Duration, Heatwaves May Be Causing 3,400 to 30,000 Excess Deaths Every Year in India: StudyTheWire.in · 30 May 2026
- Too hot, too humid: why the sustained heatwave in India and Pakistan is so dangerousThe Conversation · 28 May 2026
- India records over 300 suspected heatstroke cases as summer temperatures spikeReuters · 22 May 2026
- Heat-related deaths 'tip of the iceberg' in India as UN sends El Niño warningABC News & Headlines – Australian Broadcasting Corporation · 02 Jun 2026
- In photos: North India braces for heatwaves as temperatures cross 40CBBC · 24 Apr 2026
- Extreme temperature events and their relationship with excess all-cause mortality in Chandigarh, IndiaNature · 29 Jan 2026
- Estimating heatwave-induced excess mortality in India's districtsFrontiers · 11 May 2026
- Lost in the heat: The critical miscalculation in India’s heatwave mortality dataDown To Earth · 10 Apr 2025
- Heatwave Across India to Abate Soon But Leaves Trail of Deaths, Power Demand Hits Record PeakTheWire.in · 27 Apr 2026
- Extreme weather events in India 2024: Heatwaves, avoidable deaths and an uncertain futureDown To Earth · 21 Feb 2025
- India heatwave kills at least 33, including election officialsReuters · 31 May 2024
- India heatwave: High temperatures killing more Indians now, Lancet study findsBBC · 26 Oct 2022
- Seeing red: India had over 700 heat deaths in 2024, much higher than official toll, claim scientistsDown To Earth · 13 Sep 2024
- Climate Change made devastating early heat in India and Pakistan 30 times more likelyWorld Weather Attribution · 23 May 2022
- Heatwave: Is India ready to deal with extreme temperatures?BBC · 18 Apr 2023
- Heatwave in India: Country faces record temperature, death toll rises amid election seasonThe Times of India · 31 May 2024
- Northern India Endures a Heat Wave, and a Wave of Deaths (Published 2023)The New York Times · 18 Jun 2023
- Extended heatwave in India, Pakistan to test survivability limits, with temperatures reaching Death Valley levelsCNN · 15 Apr 2025
- India heatwave: Delhi temperature hits 47C as north India reelsBBC · 27 May 2020
- At least 50 deaths blamed on India heat wave in just a week as record temperatures scorch the countryCBS News · 03 Jun 2024
- Increasing probability of mortality during Indian heat wavesScience | AAAS · 07 Jun 2017
- In photos: North India braces for heatwaves as temperatures cross 40CBBC · 24 Apr 2026
- India's hospitals overwhelmed as heatwave death toll reaches 170Euronews.com · 20 Jun 2023
- India heatwave continues as death toll exceeds 1,000The Guardian · 28 May 2015
- India heatwave: Nearly 170 dead as northern states swelter amid soaring temperaturesSky News · 19 Jun 2023
- Hundreds die in Indian heatwaveThe Guardian · 30 May 2010
- India heatwave kills more than 500 with temperatures nearing 50CABC News & Headlines – Australian Broadcasting Corporation · 25 May 2015
Publishers: BBC (5) · The Guardian (3) · Down To Earth (3) · Euronews.com (2) · TheWire.in (2) · Reuters (2) · ABC News & Headlines – Australian Broadcasting Corporation (2) · Carnegie Endowment for International Peace (1) · NDTV (1) · Jacobin (1) · India Today (1) · Al Jazeera (1) · The Conversation (1) · Nature (1) · Frontiers (1) · World Weather Attribution (1) · The Times of India (1) · The New York Times (1) · CNN (1) · CBS News (1) · Science | AAAS (1) · Sky News (1)
Who is watching
India runs a daily satellite heat outlook. Its layer list makes the same argument this page does.
India's own heat product does not measure heat with temperature alone. Two of its four layers add moisture. Two express the answer as a departure from normal. That is the official instrument agreeing, in its design, with the two things this page had to compute for itself.
What it covers, read from its own index
1,027 days, 2022-04-29 to 2026-06-19 — the portal is current. It serves map images, so no reading on this page comes from it.
Source. Bhuvan, National Remote Sensing Centre, ISRO — Heatwave / Hot Weather Outlook.
What you can do
Heat kills the people who cannot leave it.
The season starts 1 March
Not May, when the headlines arrive. Construction and delivery workers, street vendors, anyone whose room does not cool at night — they are exposed from the first week.
Ask for the plan
Cities write Heat Action Plans. Ask if yours has one, whether it names shaded spaces and water points near your ward, and whether outdoor workers were consulted. A plan nobody can find is not a plan.
Shade is infrastructure
A tree over a bus stop does more for a waiting body than any advisory. It is the one place a heat page and a forest page meet.
Every figure here is public, dated and reproducible from the source named beside it — including the ones that do not support the argument.
A gap is a gap
An empty day stays empty — a gap in the record is a gap in the record, never a zero.
Cite this page
Reuse freely — CC BY 4.0. Every figure carries its source and its cadence in how the number is made. If you quote a number from here, quote the kind with it. Each upstream source keeps its own terms.
This is what we are doing.
It is not enough.
The work against this reading
Eco Action builds the small green infrastructure a city actually has room for — over seventy butterfly parks and over twenty herb gardens across Delhi NCR. In one Vasant Kunj park, green cover went from 5% to 90% over a decade.
And why it is not a reply
That is one park, and heat is regional. Shade cools the body standing under it and nothing past that: it does not lower the 48.3°C in this archive and it did not prevent the 1,832 deaths recorded in 2024. A canopy is a real intervention at the scale of a bus stop. The reading is at the scale of a country.
Understand the data
- What is a heatwave?In India it is a defined meteorological event, and the definition is not simply "very hot".
- How does India define a heatwave?The exact IMD rule, gate by gate, including the part that catches the coast out.
- Heatwave or extreme heat?One is a declared meteorological event. The other is what actually kills people.
Once a month, what these numbers did.
One email. What the six readings did that month, what moved and what did not, and what we did about it. Nothing else, ever — no appeals between digests, and your address is never shared with anybody.
Confirm by email before anything is stored. Every message carries a one-click link to stop them.