2025 Ranks Among Hottest Years on Record, Even as La Niña Offered Little Relief

The planet just notched another year near the top of the temperature charts, even in conditions that should have brought some relief.

2025 joins the hottest years on record

Global climate data released Jan. 14 by three major scientific agencies show that 2025 ranked among the three warmest years ever recorded worldwide and was the fourth-warmest in the contiguous United States. The findings cap an 11‑year run in which every year has landed in the top tier of global heat records and confirm that the last three years, taken together, averaged more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial temperatures.

The reports—from the European Union’s Copernicus Climate Change Service, the U.N. World Meteorological Organization (WMO) and the U.S. National Oceanic and Atmospheric Administration (NOAA)—are based on independent but broadly consistent datasets. Together, they depict a climate system in which long‑term warming from greenhouse gas emissions is now overpowering natural swings such as La Niña, a Pacific Ocean pattern that typically cools the planet.

“2025 started and ended with a cooling La Niña and yet it was still one of the warmest years on record globally because of the accumulation of heat‑trapping greenhouse gases in our atmosphere,” Celeste Saulo, secretary‑general of the WMO, said in a statement announcing the new assessment.

How the agencies ranked 2025

Globally, Copernicus ranked 2025 as the third‑warmest year in records that stretch back to the mid‑19th century, slightly cooler than 2023 and the record‑hot year of 2024. NOAA’s global analysis also placed 2025 in third place, estimating that the planet’s average surface temperature was about 1.17°C (2.11°F) above the 20th‑century average and roughly 1.34°C (2.41°F) above the 1850–1900 baseline often used as a preindustrial reference.

The WMO, which combines eight major datasets maintained by national and international centers, said 2025 can be described as “one of the three warmest years on record,” with two datasets ranking it second and six ranking it third. The agency estimated the global temperature last year at 1.44°C (2.59°F) above the preindustrial average, plus or minus 0.13 degrees.

A key marker: the 1.5°C threshold over multiple years

Behind those annual rankings lies a more consequential marker. Copernicus reported that the average temperature from 2023 to 2025 exceeded 1.5°C above preindustrial levels for the first time in its records. The WMO’s combined datasets put the same three‑year period at about 1.48°C, within the margin of error of that threshold.

Under the 2015 Paris climate agreement, nearly every nation pledged to hold long‑term global warming “well below” 2°C and to “pursue efforts” to limit the rise to 1.5°C. That target refers to a multi‑decadal average rather than a single year or a brief period, and scientists stress that the world has not yet irreversibly crossed it. But the new data suggest that a climate once described as a 1.5‑degree future is increasingly a present‑day reality.

“1.5°C is not a cliff edge,” Samantha Burgess, deputy director of the Copernicus Climate Change Service, said in remarks released with the new analysis. “However, we know that every fraction of a degree matters, particularly for worsening extreme weather events.”

Oceans and ice continued to signal accelerating change

NOAA found that much‑warmer‑than‑average conditions covered most of the Earth’s land and ocean surfaces last year, with especially large warm anomalies over the Arctic, Europe, western and southern Asia, and parts of Antarctica. Ocean heat content in the upper 700 meters reached a record high for the fifth year in a row, as the seas continued to absorb the bulk of the excess heat from human‑caused climate forcing.

Sea ice and snow—key components of the planet’s reflective cryosphere—also continued to decline:

• Arctic sea ice had its second‑lowest annual average extent on record and hit its smallest winter maximum ever observed by satellites on March 22, 2025.
• Antarctic sea ice recorded its third‑lowest annual extent, with the seasonal minimum tying 2022 and 2024 for the second‑lowest mark.
• Combined Arctic and Antarctic sea ice reached a record low in February.
• In the Northern Hemisphere, snow cover over land was the third‑lowest annual extent since records began in 1967.

Extreme events around the world

These background shifts formed the backdrop for a series of high‑impact weather disasters.

In Southeast Asia, intense rains and landslides late in the year killed more than 1,700 people, according to tallies cited by U.N. and media reports. Heat waves set new national or regional records in countries including Türkiye, Japan and Spain. Several European nations saw unusually intense wildfire seasons, with Spain and Greece among those reporting high fire‑related emissions.

Over the world’s oceans, NOAA counted five Category 5 tropical cyclones in 2025. In the Atlantic, Hurricane Melissa made landfall in Jamaica at peak intensity and tied the 1935 Labor Day Hurricane as the strongest landfalling Atlantic hurricane on record, with sustained winds estimated at more than 185 mph. Despite the strength of storms over open water, no hurricanes struck the United States or its territories last year, the first such season since 2015.

The U.S. picture: heat in the West, costly disasters nationwide

The annual climate summary from NOAA’s National Centers for Environmental Information reported that the lower 48 states recorded an average temperature of 54.6°F, 2.6°F above the 20th‑century average—enough to rank fourth‑warmest in 131 years of consistent recordkeeping. Temperatures were above average across the nation, with the greatest departures in the western third of the country.

From the Pacific Coast across the Sierra Nevada and Rockies, the region as a whole saw its warmest year on record. The Southwest climate region also notched its highest annual temperature in the historical record. Utah and Nevada each set new statewide records for warmth, 4.3°F and 3.7°F above their 20th‑century annual averages, respectively. A dozen other states logged one of their four warmest years.

A federal “snow drought” update issued in early January reported that California, Nevada, Washington, Wyoming, Colorado, Arizona, Utah and New Mexico all experienced their warmest December on record in 2025—conditions that limited mountain snowfall that many Western communities rely on as a natural reservoir for spring and summer water supplies.

Flooding, wildfires and tornadoes

For the contiguous United States as a whole, 2025 was slightly drier than average, with annual precipitation of 29.19 inches, about three‑quarters of an inch below the 20th‑century mean. But totals varied sharply by region and season, and extreme events punctuated the year.

In early July, torrents of rain over the Texas Hill Country produced what hydrologists described as a 1‑in‑100 to 1‑in‑1,000‑year flood in some watersheds. Nearly two feet of rain fell in just a few days. Floodwaters killed at least 135 people, including 27 children and counselors at a summer camp along the Llano River, according to federal summaries of the event.

Elsewhere, slow‑moving storms triggered what meteorologists classify as 1‑in‑1,000‑year‑type rainfall events in parts of Kentucky, Tennessee, North Carolina and Texas. The National Weather Service issued 1,434 flash flood warnings in July, the second‑highest total for that month in four decades of records.

On the West Coast, a parade of Pacific atmospheric river storms in February, November and December brought destructive flooding, landslides and wind damage to California and the Pacific Northwest. Earlier in the year, two winter wildfires in Southern California—the Eaton and Palisades fires—became the second‑ and third‑most destructive blazes in state history, damaging or destroying more than 18,000 structures and killing 31 people. Nationwide, about 72,000 wildfires burned 5 million acres, fewer acres than the long‑term average but with more activity in developed zones.

Severe convective storms also surged. Preliminary counts show 1,559 tornadoes across the United States in 2025, about 27% above the 1991–2020 annual average and the fifth‑highest total on record. March alone generated about 300 tornado reports, the most ever recorded for that month. An EF5 tornado struck near Enderlin, North Dakota, the first such storm confirmed in the country since 2013. North Dakota logged 72 tornadoes for the year, breaking its previous record.

NOAA’s U.S. Climate Extremes Index, which tracks the area of the country experiencing unusual heat, cold, precipitation and drought, was 58% above average in 2025, the 12th‑highest value in 116 years of record.

What scientists say comes next

Scientists say such extremes are consistent with a climate that is shifting into a warmer regime. A hotter atmosphere can hold more moisture, increasing the odds of intense downpours, while higher baseline temperatures make heat waves more likely and more severe. Warmer winters in regions that once depended on reliable snowpack can also reshape water supplies, agriculture and wildfire risk.

The data released this week are likely to feed into a wide range of policy, legal and financial decisions. Governments are preparing to update their national climate pledges under the Paris accord later this decade. Regulators are weighing rules on climate‑risk disclosure and infrastructure resilience. Courts in several countries are hearing lawsuits that hinge, in part, on the attribution of specific damages to long‑term warming.

Kristen Sissener, executive director of the research group Berkeley Earth, said in a recent interview about the emerging global record that the rapid rise in temperatures “underscores how quickly the climate system can change, and how essential sustained monitoring is to understanding those changes in real time.”

For now, the monitoring points in a clear direction. Since 2015, the world has set or come close to setting a global temperature record virtually every year. The three‑year period from 2023 to 2025—the first to average at or above 1.5°C of warming—unfolded during a time when a natural cooling phase was in place for part of the year.

That combination, scientists say, is less a surprise than an indication that the baseline has shifted. Unless emissions of carbon dioxide and other heat‑trapping gases begin a sustained and steep decline, future annual climate reports are likely to resemble the 2025 assessments: record‑setting warmth, eroding ice and snow, and a growing catalog of extreme events in every region of the world.