2025 hottest years on record: The World Meteorological Organization says 2025 is set to rank second or third, with January–August averaging about 1.42°C above the 1850–1900 baseline—showing extreme heat is persisting even as El Niño influence weakened.
What the new updates say
The World Meteorological Organization (WMO) reported in its 2025 “State of the Global Climate Update” that this year is likely to finish as either the second or third warmest in the modern observational record.
WMO also said the last 11 years (2015–2025) will each rank among the 11 warmest years in a record stretching back roughly to the mid-1800s, with 2023–2025 expected to be the three warmest years on record.
The update was released as a climate snapshot for policymakers and negotiators, and WMO said its final “State of the Global Climate” report for the full year 2025 is scheduled for March 2026.
A separate official outlook shared via WMO’s “News from Members” highlighted the UK Met Office expectation that 2025 would likely land among the three warmest years globally, just behind the record-setting conditions of 2024.
That same Met Office outlook noted 2024 was expected to be the warmest year on record and “almost certain” to exceed 1.5°C above pre-industrial levels for the first time, following a record-breaking 2023 that it placed at about 1.45°C above pre-industrial levels.
How hot 2025 has been so far
WMO said the mean near-surface temperature for January–August 2025 was about 1.42°C (±0.12°C) above the pre-industrial average (1850–1900).
WMO also emphasized that 2025’s January–August level was lower than 2024’s annual value (about 1.55°C ±0.13°C above pre-industrial), but still exceptionally high in a longer-term warming trend.
According to WMO, June 2023 through August 2025 featured an extended run of monthly record-breaking global temperatures, with February 2025 noted as an exception.
Outside annual summaries, national climate monitoring continues to show unusually warm months during 2025.
For example, NOAA’s National Centers for Environmental Information reported October 2025 as the third-warmest October in its 176-year record, at 1.23°C above NOAA’s 20th-century baseline.
Where the numbers come from (and why they may differ)
WMO said its temperature assessment draws on six international datasets, and the 2025 update used data through August 2025 rather than the full year.
That matters because different agencies use different baselines (such as 1850–1900 “pre-industrial” versus 1901–2000 or 20th-century averages), and rankings can shift slightly depending on the dataset and final year-end data.
Quick snapshot table: recent warmth
| Year / period | What agencies said | Reported warmth level (as stated) |
| 2023 (annual) | UK Met Office described 2023 as record-breaking and cited ~1.45°C above pre-industrial. | ~1.45°C above pre-industrial. |
| 2024 (annual) | WMO cited ~1.55°C (±0.13°C) above pre-industrial for 2024 and described it as hotter than 2025’s Jan–Aug period. | ~1.55°C above pre-industrial. |
| 2025 (Jan–Aug) | WMO said 2025 is set to be 2nd or 3rd warmest; Jan–Aug averaged ~1.42°C (±0.12°C) above pre-industrial. | ~1.42°C above pre-industrial. |
Why temperatures stayed extreme even as El Niño eased
WMO said warming El Niño conditions that boosted global temperatures during 2023 and 2024 gave way to neutral/La Niña conditions in 2025.
Even with that shift, WMO stressed that heat-trapping greenhouse gas concentrations and ocean heat content—both at record levels in 2024—continued to rise in 2025.
In other words, the underlying warming “floor” is being lifted by long-term climate change drivers, so natural variability (El Niño/La Niña) now plays out on top of a hotter baseline.
WMO also pointed to additional contributors to recent warmth beyond the El Niño cycle, including reductions in aerosols and other factors that likely played a role in the warming.
This combination helps explain why 2025 can remain near the very top of historical rankings even without the same El Niño push seen in 2023–2024.
Beyond temperature: sea ice, sea level, and warning systems
WMO warned that several major climate indicators kept moving in an unfavorable direction in 2025.
It said Arctic sea ice extent after the winter freeze was the lowest on record, while Antarctic sea ice extent tracked well below average throughout the year.
WMO also reported that the long-term sea level rise trend continued, even if there was a small, temporary short-term “blip” linked to naturally occurring factors.
WMO framed these indicators as part of the real-world impacts of continued warming, alongside increased disruption from extreme weather.
It also highlighted progress on early warning capabilities, saying the number of countries reporting multi-hazard early warning systems more than doubled from 56 to 119 by 2024—while noting 40% of countries still lack these systems.
Key indicators mentioned by WMO (2025 update)
| Indicator | What WMO reported | Why it matters |
| Greenhouse gas concentrations | Record levels helped drive record heat; concentrations continued rising in 2025. | Higher concentrations trap more heat and raise long-term risk. |
| Ocean heat content | Record levels reached in 2024 continued rising in 2025. | Ocean heat shapes weather extremes and sea level rise. |
| Arctic sea ice | Lowest extent on record after the winter freeze. | Low ice accelerates warming and affects ecosystems. |
| Antarctic sea ice | Well below average during the year. | Adds to concerns about polar stability and ocean circulation. |
| Sea level | Long-term rise continued despite short-term natural variability. | Raises coastal flooding and storm surge risks. |
| Early warning systems | Countries reporting multi-hazard systems rose from 56 to 119 by 2024; 40% still lack them. | Early warnings reduce deaths and economic losses. |
What this means for the 1.5°C goal—and what comes next
WMO quoted its Secretary-General Celeste Saulo saying that, without urgent action, it will be “virtually impossible” to limit warming to 1.5°C in the next few years without temporarily overshooting it, while stressing that bringing temperatures back down by the end of the century remains possible if emissions fall quickly.
WMO also relayed the UN Secretary-General’s warning that each year above 1.5°C increases economic damage and inequality, reinforcing the urgency of rapid emissions cuts.
At the same time, WMO’s update underscored that “1.5°C” in the Paris Agreement is about long-term warming, not whether a single year spikes above the threshold.
Looking ahead, WMO’s “Global Annual to Decadal Climate Update (2025–2029)” said there is an 80% chance that at least one year between 2025 and 2029 will be warmer than the warmest year on record (which WMO identified as 2024 in that update).
That same WMO outlook also indicates that the near-term risk of record warmth remains high even if individual years shuffle between first, second, and third place.
Final thoughts
Two separate official climate messages—WMO’s 2025 global update and the Met Office outlook shared via WMO—point to the same bottom line: even when short-term natural patterns shift, the planet is staying near record heat levels.
The strongest signal for readers and policymakers is not whether 2025 finishes second or third, but that the “top-three hottest” club is now dominated by consecutive recent years, reinforcing how quickly the climate baseline is changing.
The next major checkpoint will be WMO’s full-year 2025 global climate report expected in March 2026, which should firm up final rankings and consolidate the year’s global indicators.
