September 2026: Second-Hottest on Record
Why in News?
- On 13 October 2026, Down To Earth reported that the Copernicus Climate Change Service rated September 2026 the second-hottest September on record. It was 0.11°C cooler than September 2023.
- The global average temperature was 16.27°C, which is 0.82°C above the 1991-2020 average and 1.63°C above pre-industrial levels of 1850-1900.
- Sea surface temperature for the oceans outside the polar regions hit a September record of 21.05°C, beating the 20.92°C of 2023.
- The Niño 3.4 region reached an all-time monthly high of 29.70°C, which the service said shows exceptional intensity for the current El Niño.
- August 2026 was the joint-hottest August on record at 1.65°C above pre-industrial levels, so September was the second straight month above 1.5°C.
Key Terminologies
- Pre-industrial level
- The average global temperature of 1850-1900, used as the baseline to measure warming. September 2026 was 1.63°C above it.
- Sea surface temperature
- The temperature of the ocean's top layer. The record of 21.05°C refers to oceans between 60°S and 60°N, outside the polar regions.
- Niño 3.4 region
- A central Pacific zone used to track El Niño. It reached an all-time monthly high of 29.70°C in September 2026.
- Climate normal
- The 30-year average used as a reference. The 1991-2020 average is the comparison for the 0.82°C anomaly.
Key Issues
- Near Record: September 2026 trailed only September 2023 by 0.11°C. It stood 1.63°C above pre-industrial levels.
- Two Months Above 1.5°C: August was 1.65°C above pre-industrial levels and September 1.63°C. September was the second straight month above 1.5°C.
- Ocean Heat: The 21.05°C sea surface record for September beats 20.92°C of 2023. Warm oceans store heat and feed extreme weather.
- El Niño Intensity: The Niño 3.4 monthly high of 29.70°C is exceptional, and the World Meteorological Organization forecast on 8 October that the event would reach about +3.7°C for October-December.
- Two Baselines: Copernicus compares the month with 1991-2020, giving 0.82°C, and with 1850-1900, giving 1.63°C. The 0.81°C gap shows how much warming had already occurred before the 1991-2020 period, which is an inference from the two figures.
- Link to India: The 2026 southwest monsoon ended at 87 per cent of the Long Period Average, as in our report on the monsoon retreat, and the World Meteorological Organization expects drier-than-normal conditions over the Indian subcontinent.
Key Implications
Positive/Pros/Merits
- Early Warning Data: Monthly climate bulletins give governments and farmers months of notice of heat and rainfall shifts.
- Forecast Skill: The India Meteorological Department said its ENSO forecasts for the 2026 monsoon were broadly consistent with the observed evolution.
- Capacity Building: Mission Mausam, with Rs 2,000 crore over two years, plans radars, supercomputers and finer models to improve forecasts.
Negative/Cons/Demerits
- Climate Risk: Two straight months above 1.5°C and a record ocean surface raise the risk of heat extremes. The World Meteorological Organization said August 2026 was the hottest August on record.
- Drought Pressure: A strong El Niño and a deficient monsoon add to water and food stress in India, which is an inference from the data.
- Rising Baseline: With ocean surface and El Niño readings at or near records, a cooler year is unlikely to bring September temperatures back to earlier levels soon. This is an inference and not a forecast by the service.
- Uncertain Local Effects: Global records do not map directly onto local weather, and India-specific effects remain uncertain.
Key Initiatives
- Copernicus Climate Change Service: Its monthly bulletin ranked September 2026 second-warmest on record and gave the sea surface and Niño 3.4 figures.
- World Meteorological Organization, 8 October 2026: It forecast record sea-surface temperatures in October-December 2026 and a near-100 per cent likelihood that El Niño persists through February 2027.
- Mission Mausam: The Ministry of Earth Sciences mission was approved with Rs 2,000 crore over two years, with Phase-I in 2024-26 and Phase-II in 2026-31.
- India Meteorological Department: It issues seasonal and daily forecasts, and its season summary of 30 September 2026 said ENSO forecasts matched the observed evolution.
The Copernicus Climate Change Service says the Niño 3.4 reading shows exceptional intensity for the current El Niño. The World Meteorological Organization says El Niño is expected to persist through February 2027. In India, the Ministry of Earth Sciences continues Mission Mausam and the India Meteorological Department issues its forecasts.
Director's Perspective
Way Forward
- Use the monthly climate bulletins in district advisories, especially for rabi sowing in drier regions.
- Plan heat-action measures early in cities and rural areas, since heat risk stays high while ocean temperatures are at records.
- Publish regional El Niño impact outlooks for India under Mission Mausam Phase-II.
- Track ocean temperatures in the Indian Ocean as well as the Pacific, since both shape rainfall over India.
September 2026 confirms that the world is running very warm, with ocean heat and El Niño at or near records. Two straight months above 1.5°C, a record sea surface and an exceptional Niño 3.4 reading form a consistent picture. What remains uncertain is the local impact on India. In a Mains answer, credit the monitoring and early warning, then conclude that India must turn global signals into district-level advisories and water planning.
GS Relevance
Frequently Asked Questions
How hot was September 2026 globally?
September 2026 was the second-hottest September on record, 0.11°C cooler than September 2023, according to the Copernicus Climate Change Service. The global average was 16.27°C, which is 0.82°C above the 1991-2020 average and 1.63°C above pre-industrial levels.
What was the sea surface temperature record in September 2026?
The sea surface temperature for the oceans outside the polar regions reached a September record of 21.05°C, beating the previous record of 20.92°C set in 2023. The Niño 3.4 region also reached an all-time monthly high of 29.70°C.
What does the pre-industrial baseline mean in climate reports?
The pre-industrial baseline is the average global temperature of 1850-1900, used to measure warming. September 2026 was 1.63°C above it, and it was the second straight month above 1.5°C after August 2026 at 1.65°C above.
PYQ Practice — Statement Analysis
1 The pre-industrial baseline in climate reports refers to the period 1850-1900.
September 2026 was 1.63°C above this baseline.
2 September 2026 was the hottest September on record, ahead of September 2023.
It was the second-hottest, 0.11°C cooler than September 2023.
3 The Niño 3.4 region is used to track El Niño in the central Pacific.
It reached an all-time monthly high of 29.70°C in September 2026.