heat island
noun
plural heat islands
: an urban area that experiences higher atmospheric temperatures than the surrounding environment (as due to having less greenery and more structures that absorb and retain heat)
—often used before another noun
factors that contribute to a heat island effect
Examples of heat island in a Sentence
Recent Examples on the Web
The heat spreads, contributing to what’s known as the urban heat island effect, said Vincent Cotrone, extension educator of urban forestry at Pennsylvania State University.
—
Aya Diab, Fortune, 23 May 2026
Fans attending games will also be subject to the urban heat island effect, when major cities become significantly hotter than nearby rural areas.
—Elias Burke, New York Times, 21 May 2026
Without the cooling effect of trees, the urban heat island effect across the world’s cities would be twice as hot, a new study by The Nature Conservancy found.
—Natasha Bracken, semafor.com, 7 May 2026
The Kansas City metro is not included in the advisory because the urban heat island may keep temperatures warmer, according to the weather service.
—Kansas City Star, 1 May 2026
Urban farms like Harlem Grown not only improve food security, but also climate resilience—lowering the carbon footprint of food production and reducing the effects of heat islands that cities are often prone to.
—Simmone Shah, Time, 30 Apr. 2026
These heat islands, as they’re called, experience surface temperatures that far exceed outside ambient temperatures.
—Sacoby Wilson, Baltimore Sun, 29 Apr. 2026
For example, for animals that have evolved to breed at a specific time of the year, urban heat islands can select for earlier breeding.
—Daniel T. Blumstein, The Conversation, 8 Apr. 2026
In a city, the first 100 meters (328 feet) of earth act as a thermal sponge, soaking up heat from human activity—what Philipp Blum, a professor of engineering geology at Germany’s Karlsruhe Institute of Technology, calls the subsurface urban heat island.
—Vanessa Bates Ramirez, Scientific American, 18 Feb. 2026
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Aya Diab, Fortune, 23 May 2026
Fans attending games will also be subject to the urban heat island effect, when major cities become significantly hotter than nearby rural areas.
—Elias Burke, New York Times, 21 May 2026
Without the cooling effect of trees, the urban heat island effect across the world’s cities would be twice as hot, a new study by The Nature Conservancy found.
—Natasha Bracken, semafor.com, 7 May 2026
The Kansas City metro is not included in the advisory because the urban heat island may keep temperatures warmer, according to the weather service.
—Kansas City Star, 1 May 2026
Urban farms like Harlem Grown not only improve food security, but also climate resilience—lowering the carbon footprint of food production and reducing the effects of heat islands that cities are often prone to.
—Simmone Shah, Time, 30 Apr. 2026
These heat islands, as they’re called, experience surface temperatures that far exceed outside ambient temperatures.
—Sacoby Wilson, Baltimore Sun, 29 Apr. 2026
For example, for animals that have evolved to breed at a specific time of the year, urban heat islands can select for earlier breeding.
—Daniel T. Blumstein, The Conversation, 8 Apr. 2026
In a city, the first 100 meters (328 feet) of earth act as a thermal sponge, soaking up heat from human activity—what Philipp Blum, a professor of engineering geology at Germany’s Karlsruhe Institute of Technology, calls the subsurface urban heat island.
—Vanessa Bates Ramirez, Scientific American, 18 Feb. 2026
Cite this Entry
“Heat island.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/heat%20island. Accessed 9 Jun. 2026.
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