Climate Central’s Monthly Briefing Highlights from August 2025

What do experts say?

Dr. Zachary Labe, Climate Scientist at Climate Central, said: 

Even though parts of the U.S. saw slightly cooler conditions in August compared to recent years, near-record warmth persisted across much of the globe, highlighting the ongoing impact of climate change on communities around the world.

Global Climate:

• August 2025 was the 3rd warmest August on record globally, after 2023 and 2024.

• All ten of the warmest Augusts on record have occurred since 2015.

• Regionally, it was the 4th warmest over land and the 3rd warmest over oceans.

• Arctic sea-ice extent ranked as the 7th lowest on record for August.

• Antarctic sea-ice extent was the 3rd lowest for the month.

U.S. Climate:

• August 2025 ranked as the 28th warmest August on record nationwide.

• Arizona experienced its 2nd warmest August on record.

• The month was the 23rd driest August on record, with record dryness in Kentucky, Ohio, and Vermont.

• Twelve states recorded one of their ten driest Augusts on record.

• As of September 9th, at least 60% of the U.S. is experiencing abnormally dry or drought conditions.

Climate Moment of the Month:

• A major marine heatwave continues across the North Pacific Ocean, with sea surface temperatures reaching new record high levels during the month of August. According to the Climate Shift Index: Ocean, climate change made these ocean temperatures at least 50-200x more likely. The unusual warmth is forecast to continue into October, which may influence regional weather patterns across North America.

Climate Extremes and the Climate Change Element:

• While many areas across the United States observed cooler conditions than the 1991-2020 average, a fingerprint of climate change influence was still evident using the Climate Shift Index (CSI).

• Twenty-seven cities across the country experienced at least two weeks' worth of days at or above a CSI 2. See more in Climate Central’s August 2025 attribution overview.

• Notable Temperature Event: Phoenix reached a new August record for daily high temperature, hitting 118°F on August 7.

• Notable Precipitation Event: Honolulu, Hawaii received no measurable rainfall for the month of August, which hasn’t occurred since 1974.

Climate Outlook:

• Global Climate: Global temperatures are expected to remain elevated, with 2025 increasingly likely to rank among the top three warmest years on record.

• El Niño-Southern Oscillation (ENSO): La Niña conditions are expected to persist through October-December, with cooler-than-average sea surface temperatures across the equatorial Pacific.

• Drought: Ongoing drought is likely to continue across the Western U.S., with potential drought development in the Midwest and into the Middle Atlantic region.

• Temperature: There is an increased likelihood of above average temperatures across Alaska and the contiguous U.S. over the next three months.

• Precipitation: September-November is forecast to bring drier-than-average conditions to the Southern Plains and Southwest, while wetter-than-average conditions are more likely in Western Alaska, the Pacific Northwest, and Florida.

• Energy: The number of cooling degree days across the contiguous U.S. was the 10th highest on record for the summer of 2025 (June-July-August).

Data:

Global and U.S. climate statistics are provided by NOAA’s National Centers for Environmental Information (NCEI), including through the Climate at a Glance tool. Data is also provided by the Applied Climate Information System (ACIS), which is developed, maintained, and operated by NOAA’s Regional Climate Centers. We recognize that climate ranking statistics can vary slightly between datasets. Drought information is available through the U.S. Drought Monitor. Seasonal temperature and precipitation outlooks are from the NOAA Climate Prediction Center.

Additional Resources:

• Monthly Climate Reports | National Climate Report | August 2025 | National Centers for Environmental Information (NCEI)

• Monthly Climate Reports | Global Climate Report | August 2025 | National Centers for Environmental Information (NCEI)  

• Drought Monitor

• Climate Prediction Center: ENSO Diagnostic Discussion  

• Climate Central Program Page for Climate Services

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