Storm at sea. Photo: Shutterstock According to a report published in 2025 by the National Centers for Environmental Information of the US National Oceanic and Atmospheric Administration (NOAA), the world's oceans absorbed an unprecedented amount of heat.
NOAA ranked 2025 as the third-warmest year ever measured in its global temperature record, which began in 1850. “The annual global surface temperature was 2.11°F (1.17°C) above the 20th-century average, falling behind the record-setting year of 2024 (by 0.22°F/0.12°C) and the second-warmest year, 2023 (by 0.04°F/0.02°C). The 10 warmest years in the historical record have all occurred since 2015. Additionally, 2025 exceeded the pre-industrial (1850–1900) average by 2.41°F (1.34°C),” the report notes.
The past year has been marked by temperatures well above average across much of the Earth's surface. The largest warm anomalies were recorded in the Arctic, Europe, West and South Asia, and parts of Antarctica. All continents, as well as the Arctic, ranked within their ten warmest years. In particular, Europe, Oceania, and the Arctic recorded their second-warmest year on record.
Globally, land areas experienced the second warmest year on record, while ocean areas ranked third. High ocean temperature anomalies were particularly prominent in the North Pacific. In contrast, cooler-than-average conditions were observed in the central and eastern tropical Pacific and East Antarctica. Despite some areas with cooler-than-normal temperatures, no land or ocean area set a record annual cold snap.
The report also found that the heat content of the upper ocean layer (a measure of the amount of accumulated heat retained in ocean water at a given depth) was the highest ever recorded in 2025. Ocean heat content is a key climate indicator because the oceans store about 90% of the excess heat in the Earth's climate system.
The global ocean heat content at a depth of 0-700 meters, measured since 1955, has shown a consistent upward trend since the early 1970s. 2025 marks the fifth consecutive year this index has recorded its highest value.
Snow cover in the Northern Hemisphere was also below average, ranking among the three lowest on record.
As for storms, the report notes that in 2025, 101 tropical storms occurred worldwide, above the 1991-2020 average of 88. Of these, 52 reached tropical cyclone strength (winds of 74 miles per hour), and 24 reached strong tropical cyclone strength (winds of 111 miles per hour). In addition, five storms reached Category 5 (winds of 157 miles per hour).
"The global accumulated cyclone energy was about 90% of the 1991–2020 average. Global tropical cyclone activity in 2025 varied by region, with a near-average number of named storms in the North Atlantic, North Indian and Southwest Pacific and an above-average number of named storms across the rest of the basins."
Among the notable events of the past year:
The North Atlantic Ocean recorded a high number of Category 5 hurricanes. Three hurricanes, Erin, Humberto, and Melissa, reached this category in 2025. This is the secondphighest number recorded in a single year, after 2005 when four were recorded.
Hurricane Melissa in the Atlantic Ocean tied the Labor Day Hurricane of 1935 as the strongest Atlantic hurricane to make landfall, and was the world's strongest tropical storm in 2025.
In the Eastern Pacific, Hurricane Eric was the most destructive storm in the basin, becoming the first powerful hurricane to hit Mexico in a calendar year.
In the Western Pacific, Typhoon Ragasa was the only typhoon with the strength equivalent to Category 5.