Earth just had its hottest month ever recorded. On 10 September, Europe's climate agency Copernicus confirmed that August 2026 tied July 2023 for the warmest month in the record. The global average hit 16.96°C, which is 1.65°C above pre-industrial levels. It was also the first month above the 1.5°C line since November 2025 (Copernicus).
The headline is easy to read. The harder question is what it means for your tap, your water tank and your health. The answer comes down to two words: El Niño.
What is El Niño, and how strong will it get?
El Niño is declared when sea surface temperatures in the tropical eastern Pacific run at least 0.5°C above the long-term average. It returns irregularly every two to seven years (NOAA Climate.gov).
This year's numbers are striking:
- In its 10 September update, NOAA's Climate Prediction Center kept an El Niño Advisory in place. It put the chance of a "very strong" event this fall and winter (2026-27) at more than 90% (NOAA CPC).
- Columbia University's IRI reported that the Niño 3.4 index hit +2.03°C in July. In its August 2026 issuance, for October to December, 15 forecast models showed +3.0°C or higher (IRI). These are model forecasts, not certainties, but the signal is clear.
- India's weather department (IMD) expects El Niño to weaken only in February or March (Business Standard).
In other words, this is not just a monsoon story. It could shape the whole winter.
What India has seen so far
IMD figures up to 31 August (Business Standard):
- June to August rainfall was 13.8% below normal. August alone was 16.3% short.
- About 350 districts, or 47% of the country, reported deficient or very deficient rain.
- Southern peninsular India was 24.2% short. East and Northeast India was 25.7% short.
- August 2026 was India's warmest August since 1901, at 28.01°C.
- September rain is forecast to come in below 91% of the long-period average.
The monsoon is also on its way out. Around 18 September, IMD indicated that conditions are turning favourable for withdrawal from parts of West Rajasthan (IMD).
The picture is not uniform, though. IMD said parts of the North-West, North-East, East and East-Central regions could see normal or above-normal rain in September. "Drought everywhere" would be the wrong takeaway. The better summary is that rain has been very uneven.
How full are India's reservoirs?
According to the CWC bulletin of 27 August, live storage stood at 125.299 BCM (67.83% of capacity). A year earlier it was 153.083 BCM (ChiniMandi, citing CWC data).
A Dolat Capital report, carried by ANI, put all-India storage at 70.3% of capacity as of 3 September. That is 3.3% below the ten-year normal. By region (LatestLY/ANI):
- West: 81.2% full
- Central: 80.6% full
- North: 62.7% full, 18.5% below normal
- South: 56.8% full, 19.1% below normal
So the national picture is not alarming, but the buffer is thin in the north and south. If winter rain stays weak under El Niño, pressure could show up there first next summer. That is our reading of the data, not an official forecast.
One more point: a full reservoir does not guarantee water at your home. We covered this earlier, when Mumbai's lakes were about 96% full and a water cut continued anyway (read the story).
What happened the last time El Niño hit India
During the 2023-24 El Niño, IMD forecast above-normal maximum and minimum temperatures for December to February. It said El Niño was the main driver, alongside regional factors. November 2023 ranked among India's warmest Novembers since 1901, with average maximum and minimum temperatures near the top of the record (Business Standard).
Down To Earth's analysis of IMD's 2023 report found that January-February ran 0.83°C warmer than normal and October-December ran 1°C warmer. In 20 states and UTs, winter minimum temperatures were 2 to 4°C above normal (Down To Earth).
That is not a guarantee for this year. NOAA expects this El Niño to be stronger, and IMD's own next seasonal outlook will sharpen the picture. But if October and November turn out hotter than usual, it should not come as a surprise.
Staying hydrated in a hot autumn
WHO calls heat stress a leading cause of weather-related deaths. Heat-related mortality among people over 65 rose by about 85% between 2000-2004 and 2017-2021 (WHO). Children and adults over 60 are especially prone to dehydration (Johns Hopkins Medicine).
Three research-backed habits:
- Drink before you feel thirsty. The CDC's occupational health agency, NIOSH, advises this because by the time thirst hits, you are already behind. Dehydration is a primary contributor to heat exhaustion (NIOSH/CDC).
- Respect humid heat. When humidity is high, sweat evaporates more slowly and the body sheds heat less efficiently (Iowa HHS). We have already covered the warning signs of dehydration in detail (read here).
- For most people, plain water is enough. NIOSH says the same. If you work outdoors for hours or sweat heavily at the gym, an electrolyte drink can be a convenient add-on. One example is Amaayu Electrolyte Water, which the brand says contains sodium, potassium and magnesium with no sugar. For dehydration from vomiting, diarrhoea or fever, ORS and medical advice come first, and Amaayu itself states that its electrolyte water is not an ORS replacement (Amaayu).
Storing water safely when supply gets patchy
A systematic review of 57 studies concluded that water quality drops substantially between collection and consumption (PMC). Basic safe-storage rules (Emergency WASH):
- Use a lidded container with a tap or narrow opening, so hands and cups never go inside.
- Keep it off the ground, in the shade, away from children, animals and insects.
- Clean it weekly, or whenever it looks dirty.
- Keep any funnel you use for filling clean too.
We have also written about capturing rainwater at home (read here).
What to watch in the coming weeks
- 8 October: NOAA's next ENSO update, released on the second Thursday of each month.
- IMD's next seasonal outlook: this is where the winter and rainfall picture should get clearer.
- CWC's weekly reservoir bulletin: watch the northern and southern numbers closely.
Frequently asked questions
What is El Niño?
El Niño is a warming of the tropical eastern Pacific, declared when sea surface temperatures run at least 0.5°C above the long-term average. It recurs every two to seven years.
Will El Niño make India's winter warmer?
It is not certain. In 2023-24, IMD forecast above-normal temperatures and named El Niño as the main driver. For this year, wait for IMD's official outlook.
Is plain water enough in hot weather?
NIOSH says water is generally sufficient for most people. Long hours outdoors or heavy sweating may call for electrolytes, and illness-related dehydration needs ORS and medical advice.
Sources
Note: The NOAA, IRI, IMD and CWC pages below are updated periodically. The figures cited here reflect the 8–10 September 2026 monthly updates and the dated bulletins noted alongside each source.
- Copernicus: August 2026 climate bulletin (10 Sep 2026)
- NOAA Climate.gov: What is ENSO / El Niño
- NOAA CPC: ENSO Diagnostic Discussion (10 Sep 2026 update)
- IRI: ENSO forecast (August 2026 issuance)
- Business Standard: IMD September outlook (31 Aug 2026)
- IMD: rainfall information and monsoon withdrawal update (accessed 18 Sep 2026)
- ChiniMandi: CWC reservoir bulletin dated 27 Aug 2026
- LatestLY/ANI: national reservoir levels report, September 2026 (data to 3 Sep 2026)
- Business Standard: IMD winter/November temperature report (Dec 2023)
- Down To Earth: IMD report on 2023
- WHO: Heat and health
- NIOSH/CDC: Heat Stress: Hydration
- Johns Hopkins Medicine: Dehydration and Heat Stroke
- Iowa HHS: Heat-related illnesses
- PMC: Household Water Treatment and Safe Storage
- Emergency WASH: Safe Water Storage
- Amaayu: Electrolyte Water FAQ
Data as of 19 September 2026.