Global Analysis: Dangerous Humid Heat Rising Due to Climate Change

Since the 1970s, the global average number of dangerous humid heat days—defined as those with a maximum wet-bulb temperature of 25°C or higher—has more than doubled, rising from 10 to 23 days per year. Climate Central's analysis indicates that human-caused climate change is now the primary driver of this trend, accounting for 64% of all such days since 1970 and 83% of the 23 dangerous days recorded in 2025. The most significant increases are observed in tropical humid regions, including Southeast Asia, coastal West Africa, and tropical South America, though increases are also noted in drier areas like the Arabian Peninsula and the southwestern United States.

• Global dangerous humid heat days have more than doubled between the 1970s and the period of 2016-2025, increasing from an average of 10 days per year to 23 days per year.
• Human-caused climate change is the primary driver of the increase in dangerous humid heat, responsible for 64% of all such days globally since 1970.
• The influence of climate change on dangerous humid heat has accelerated, with climate change responsible for six times as many such days annually compared to the 1970s; in 2025, 19 of the 23 global average dangerous humid heat days (83%) were added by climate change.
• The most substantial increases in dangerous humid heat are found in tropical humid regions, where some areas in Southeast Asia, coastal West Africa, and tropical South America now average at least six months of such days annually.
• A peer-reviewed study by Climate Central scientists found that climate change increased daily maximum wet-bulb temperatures by an average of 1.2°C (~2.2°F) across four recent humid heat events and made peak daily wet-bulb temperatures 65 to 175 times more likely.

APA

Trudeau, K. (2026). Global Analysis: Dangerous Humid Heat Rising Due to Climate Change. Climate Central. https://assets.ctfassets.net/cxgxgstp8r5d/1EWJMgG00mPaAsPmNwq5uo/913d61dbd5a18331a4847d36e980d742/Climate_Central_Report_Global_Dangerous_Humid_Heat.pdf

Chicago

Trudeau, Kaitlyn. Global Analysis: Dangerous Humid Heat Rising Due to Climate Change. Climate Central, 2026. https://assets.ctfassets.net/cxgxgstp8r5d/1EWJMgG00mPaAsPmNwq5uo/913d61dbd5a18331a4847d36e980d742/Climate_Central_Report_Global_Dangerous_Humid_Heat.pdf.

Wikipedia

{{cite report |last1=Trudeau |first1=Kaitlyn |title=Global Analysis: Dangerous Humid Heat Rising Due to Climate Change |publisher=Climate Central |date=24 June 2026 |url=https://assets.ctfassets.net/cxgxgstp8r5d/1EWJMgG00mPaAsPmNwq5uo/913d61dbd5a18331a4847d36e980d742/Climate_Central_Report_Global_Dangerous_Humid_Heat.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{trudeau2026global, author = {Trudeau, Kaitlyn}, title = {{Global Analysis: Dangerous Humid Heat Rising Due to Climate Change}}, institution = {Climate Central}, year = {2026}, month = jun, url = {https://assets.ctfassets.net/cxgxgstp8r5d/1EWJMgG00mPaAsPmNwq5uo/913d61dbd5a18331a4847d36e980d742/Climate_Central_Report_Global_Dangerous_Humid_Heat.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }