Ocean Temperatures Hit a Historic High in 2026

The pace and severity of global warming is most commonly discussed in terms of air temperature. This tendency is understandable, as atmospheric conditions impact the everyday experiences of virtually everyone–and from dangerous heatwaves to disappearing winter seasons, the Earth’s warming atmosphere can have serious implications. 

But while global warming’s impact on the atmosphere is significant, the phenomenon’s effect on the world’s oceans is no less so–and many of the consequences are equally dire. According to researchers at NASA, 90% of excess heat in recent decades has been absorbed by the ocean. And as is the case with atmospheric warming, the pace of warming in ocean waters is rapidly accelerating. Over the last 20 years, ocean temperatures have been rising at twice the rate observed between 1960 and 2005. 

The known implications of the trend include increased acidification of sea waters, which threatens underwater ecosystems and lifeforms, including coral and shellfish, as well as the industries that rely on them. Warmer waters are also expected to fuel larger and more intense hurricanes while accelerating the rate of glacial melt and sea-level rise. The Arctic alone has warmed by nearly 8°F since 1980, driving a loss of more than 190,000 square miles of ice each decade, an area roughly the size of Spain. 

As the oceans warm at an unprecedented rate, new record-high temperatures are being set–and broken–each year. 

Using data compiled by Climate Central, a non-profit research and advocacy group, Climate Crisis 247 identified the years with the highest ocean temperatures. We reviewed daily ocean surface temperature readings and calculated a single annual average temperature for each year going back to 1982. Using annual averages, we ranked the 10 years with the highest global mean ocean surface temperature. Supplemental data on 30-year baseline average temperatures and peak annual temperatures are also from Climate Central. Additional data on average air temperature in the Continental United States for each year is from the National Oceanic and Atmospheric Administration. 

10. 2021

• Average ocean surface temperature globally: 69.14°F
• Highest average ocean surface temperature in 2021: 69.47°F on March 16
• 30-year average ocean surface temperature on March 16: 68.97°F
• Average atmospheric temperature in the Continental U.S. in 2021: 54.50°F (6th warmest on record)

9. 2015

• Average ocean surface temperature globally: 69.17°F
• Highest average ocean surface temperature in 2015: 69.44°F on April 3
• 30-year average ocean surface temperature on April 3: 68.98°F
• Average atmospheric temperature in the Continental U.S. in 2015: 54.38°F (7th warmest on record)

8. 2022

• Average ocean surface temperature globally: 69.17°F
• Highest average ocean surface temperature in 2022: 69.51°F on March 12
• 30-year average ocean surface temperature on March 12: 68.95°F
• Average atmospheric temperature in the Continental U.S. in 2022: 53.38°F (21st warmest on record)

7. 2019

• Average ocean surface temperature globally: 69.17°F
• Highest average ocean surface temperature in 2019: 69.61°F on March 22
• 30-year average ocean surface temperature on March 22: 69.01°F
• Average atmospheric temperature in the Continental U.S. in 2019: 52.66°F (40th warmest on record)

6. 2016

• Average ocean surface temperature globally: 69.21°F
• Highest average ocean surface temperature in 2016: 69.78°F on March 6
• 30-year average ocean surface temperature on March 6: 68.93°F
• Average atmospheric temperature in the Continental U.S. in 2016: 54.90°F (3rd warmest on record)

5. 2020

• Average ocean surface temperature globally: 69.22°F
• Highest average ocean surface temperature in 2020: 69.70°F on March 31
• 30-year average ocean surface temperature on March 31: 68.99°F
• Average atmospheric temperature in the Continental U.S. in 2020: 54.36°F (8th warmest on record)

4. 2025

• Average ocean surface temperature globally: 69.47°F
• Highest average ocean surface temperature in 2025: 69.89°F on March 15
• 30-year average ocean surface temperature on March 15: 68.96°F
• Average atmospheric temperature in the Continental U.S. in 2025: 54.62°F (4th warmest on record)

3. 2023

• Average ocean surface temperature globally: 69.60°F
• Highest average ocean surface temperature in 2023: 69.97°F on August 24
• 30-year average ocean surface temperature on August 24: 68.74°F
• Average atmospheric temperature in the Continental U.S. in 2023: 54.36°F (9th warmest on record)

2. 2024

• Average ocean surface temperature globally: 69.69°F
• Highest average ocean surface temperature in 2024: 70.11°F on April 24
• 30-year average ocean surface temperature on April 24: 68.88°F
• Average atmospheric temperature in the Continental U.S. in 2024: 55.48°F (the warmest on record)

1. 2026 (year-to-date)

• Average ocean surface temperature globally: 69.86°F
• Highest average ocean surface temperature in 2026: 70.13°F on August 26
• 30-year average ocean surface temperature on August 26: 68.74°F
• Average atmospheric temperature in the Continental U.S. in 2026: N/A 

More from ClimateCrisis 247

• Hottest Falls In US History
• The Fish, Birds, and Mussels America Just Lost for Good
• Tornado Season Looks Different Now: Is Your State on the List?
• The Least Reliable Electric Vehicles, According to Consumer Reports