Warm Summer Nights Influenced by Climate Change

Analysis of 247 U.S. cities shows a significant increase in sweltering summer nights influenced by climate change, with average annual occurrences rising from one in the 1970s to approximately 27 currently. Nighttime temperatures have risen by an average of 3.1°F across 231 analyzed locations, with the Southwest experiencing the highest regional warming and Florida cities seeing the largest increases in climate-fueled warm nights.

• Between 1970 and 2024, average summer minimum (nighttime) temperatures increased by 3.1°F across 231 of the 241 U.S. locations analyzed.
• The Southwest region saw the most significant regional increase in summer nighttime temperatures since 1970, warming by an average of 4.5°F across 11 locations. Specific cities with the highest warming include Reno, Nev. (17.7°F) and Las Vegas, Nev. (10°F).
• The frequency of warmer-than-normal summer nights strongly influenced by climate change (CSI level 2 or higher) has risen from an average of one per year in the 1970s to approximately 27 per year currently across 246 of 247 analyzed U.S. cities.
• Florida contains the five cities with the largest increases in climate-fueled warm summer nights: West Palm Beach (62), Ft. Myers (61), Miami (60), Tampa (59), and Orlando (58).
• Increased nighttime heat exacerbates health risks and heat stress, particularly for vulnerable populations such as the elderly, pregnant people, and those with chronic illnesses. These risks are further compounded by urban heat islands and structural inequities, where people of color and those below the poverty line are disproportionately exposed to heat extremes in 169 large U.S. cities.

APA

Climate Central (2025). Warm Summer Nights Influenced by Climate Change. https://www.climatecentral.org/climate-matters/warm-summer-nights-2025

Chicago

Climate Central. Warm Summer Nights Influenced by Climate Change. 2025. https://www.climatecentral.org/climate-matters/warm-summer-nights-2025.

Wikipedia

{{cite report |author=Climate Central |title=Warm Summer Nights Influenced by Climate Change |date=11 June 2025 |url=https://www.climatecentral.org/climate-matters/warm-summer-nights-2025 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2025warm, author = {{Climate Central}}, title = {{Warm Summer Nights Influenced by Climate Change}}, institution = {Climate Central}, year = {2025}, month = jun, url = {https://www.climatecentral.org/climate-matters/warm-summer-nights-2025}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }