Have you ever woken up during the night exhausted and drenched in sweat, and found it hard to fall back asleep? Well, you’re not alone. Due to rising global temperatures, between 2020 and 2025 people lost an average of 56 hours of sleep each year, according to a study published by the organization Climate Central.
“While many factors influence sleep, nighttime heat is becoming an increasingly significant environmental risk as global temperatures rise and more people move to urban heat islands that further intensify nighttime temperatures,” the study states.
In nearly all the cities analyzed, the incidence of insomnia associated with rising temperatures has at least doubled since the early 1970s.
In the 253 U.S. cities analyzed, an average of 36 hours of sleep was lost annually due to high nighttime temperatures. Four of those hours — representing 13% — are attributed to climate change caused by human activities.
Arizona, California, Florida, and Nevada were the U.S. states with the greatest climate-change-related sleep losses: between seven and nine hours per year.
What the study says
To estimate how climate change is affecting sleep in cities, Climate Central analyzed the relationship between nighttime temperature and sleep. It considered both observed temperatures and hypothetical ones—that is, those that would have occurred in a world without global warming.
Two periods were analyzed: 2020 to 2025, and a historical period in the early 1970s. This allowed them to estimate the amount of sleep the average person lost due to high nighttime temperatures, and what percentage of this sleep loss was due to climate change.
Between 2020 and 2025, global warming resulting from climate change was responsible for a significant portion of the annual loss of sleep. It is estimated that there was a 10% annual loss of sleep, or approximately six hours.
This translates to nearly seven nights of lost sleep per year due to high nighttime temperatures, of which at least one night is directly related to climate change.
“Although the amount of temperature-related sleep loss due to climate change is relatively small, it has roughly doubled globally, rising from about two hours per year in 1970–1975 to about five hours per year in 2020–2025,” the report states.
The year 2025 was the third warmest on record, surpassed only by the historic peaks of 2023 and the all-time record set in 2024, according to the Copernicus Climate Change Service.
The impact by region
In the United States, Miami and West Palm Beach, in Florida, were the cities with the greatest loss of sleep due to extreme heat: 80 hours. Six and seven of those hours, respectively, are attributed to the impact of climate change.
The impact was less severe in other states. Residents of New Orleans, Louisiana, lost 61 hours of sleep annually, and those in New York lost 35.
In Latin America, some cities recorded between 70 and 93 hours of lost sleep due to extreme heat. Acapulco de Juárez, Mexico, and Barranquilla, Colombia, topped the list with 93 hours of insomnia.
Next were Cancún, Mexico; Cartagena, Colombia; Maracaibo, Venezuela; and São Luís, Brazil, with 91 hours lost. Barcelona, Venezuela, recorded 88 hours of annual sleep loss due to extreme heat. Meanwhile, Fortaleza and João Pessoa, Brazil, and Havana, Cuba, recorded 87 hours.
In the Middle East, residents of Saudi Arabia, Oman, and the United Arab Emirates experienced an annual reduction in sleep of between 55 and 87 hours due to rising nighttime temperatures.
Of that total, climate change is responsible for the loss of 12 to 16 hours. This represents a loss of sleep equivalent to nearly two full nights each year.
What we can do
To fall asleep during periods of extreme heat, both the Centers for Disease Control and Prevention (CDC) and the American Heart Association (AHA) recommend staying properly hydrated throughout the day, taking a lukewarm shower before bed, and adjusting the bedroom temperature to keep it as cool as possible.
The United Nations Children’s Fund (UNICEF) recommends that parents check the forecast for temperature and humidity over the next few days so they can establish a routine. This is especially important if there are infants and children under 5 in the home, as they are among the groups most vulnerable to extreme heat.
In addition, UNICEF advises keeping an emergency first-aid kit at home that contains packets of oral rehydration salts, a thermometer, bottles of cool water, damp towels or cooling cloths, a battery-powered fan or portable misting device, and a checklist for identifying and treating symptoms of heat stress.
To get the heat risk forecast for your residential area and take the recommended steps to stay safe, the CDC advises you to access your heat risk dashboard.
To find out which cooling centers are near your home or workplace, residents can contact the 2-1-1 service in their state or visit the National Center for Healthy Housing website.
