Southern India is among the hardest-hit regions in the world when it comes to sleep loss from hot nights, according to a new report by Climate Central, a US-based nonprofit of scientists and communicators.
“Climate change-linked sleep losses were also high in other already-hot places: people in southern India and several countries in Southeast Asia lost 78 to 91 hours of sleep per year due to higher nighttime temperatures, including about eight to nine hours due to climate change,” the report said.
That works out to roughly one night of sleep lost every year due to climate change, using the report’s own benchmark of eight hours as one night of sleep.
The global picture
The report, titled ‘Climate Change is Costing People Sleep’, was released on July 15, 2026. It examined 1,338 cities around the world, including 253 in the United States.
Globally, the average person lost nearly 56 hours of sleep a year due to nighttime heat between 2020 and 2025. Of this, six hours, or just over 10%, were linked to climate change. The report said this was “equivalent to nearly seven nights’ worth of sleep lost each year due to higher nighttime temperatures, including about one night linked to climate change.”
Cities in the Middle East recorded the highest climate change-linked sleep losses in the world. People in cities in Saudi Arabia, Oman and the United Arab Emirates lost between 55 and 87 hours of sleep annually due to nighttime heat, of which 12 to 16 hours were linked to climate change.
Where southern India stands
Southern India dominates the list of Indian cities losing the most sleep to climate change, Climate Central data for 2020-2025 show.
Coimbatore tops the list. People there lost 78 hours of sleep a year due to nighttime heat, with nine of those hours, or 11%, linked to climate change.
Madurai and Tirunelveli, both in Tamil Nadu, follow closely, each losing 86 to 88 hours a year, with about nine hours tied to climate change. Teni, also in Tamil Nadu, lost nine hours to climate change out of 72 hours overall, the highest share (12%) among the top 10 cities.
Bengaluru is the only major metro in the top five, losing 67 hours of sleep a year, eight of them due to climate change. Erode, Hubballi, Mysuru, Kota and Salem round out the list, each losing between seven and eight hours a year to climate change alone. Seven of the 10 worst-hit cities are in southern India.
How the rest of India ranks
After the top 10, the next tier of 13 cities all lose seven hours of sleep a year due to climate change, though they are spread across very different parts of the country.
In Rajasthan, Ajmer, Jaipur and Jodhpur fall into this band, losing between 67 and 72 hours a year due to nighttime heat overall.
Hyderabad and Kalaburagi in the Deccan region also register seven hours, as do Sangli and Sholapur in Maharashtra. Tamil Nadu adds two more cities to this tier, Kallakurichi and Tiruchirappalli, while Andhra Pradesh contributes three—Guntur, Vijayawada and Nellore. Jamshedpur in Jharkhand is the only eastern city in the group.
What sets this tier apart is how differently the same seven-hour climate change loss plays out as a share of each city’s total burden. In Nellore, which loses 92 hours a year overall—the highest in this group—climate change accounts for just 7% of the loss. In Jaipur and Jodhpur, where overall losses are far lower, at around 67 to 72 hours, the same seven hours make up closer to 10% of the total.
This pattern, seen across the data, shows that cities that were already extremely hot see climate change add a similar number of hours, but a proportionally smaller share, than historically milder cities.
Change since the 1970s
The report also compared the current period with the early 1970s and found that the climate change-linked share of sleep loss has grown almost everywhere.
In the average city studied, sleep loss due to climate change increased from about two hours a year in 1970-1975 to about five hours a year in 2020-2025, roughly doubling.
The report said, “the climate change-linked portion of this sleep loss has at least doubled since the early 1970s in nearly every city analyzed (1,335 of 1,338) and has at least tripled in 840 of those cities.”
The report cited earlier research showing that some groups face greater sleep loss from hot nights than others. It said the effect of warmer nighttime temperatures “is more than twice as large for adults over 65 as for middle-aged adults, and nearly three times as large for people in lower-middle-income countries as for people in high-income countries.” Women and people already living in hot climates also showed greater effects, the study found.
The role of cooling
Air conditioning can reduce the impact of hot nights on sleep, but the report noted that access to cooling remains linked to income. Household air-conditioning ownership stood at about 35% worldwide in 2021, the report said, and remains unequal in many hot countries, including parts of South Asia and Africa.
The report also flagged a limitation in the underlying research. It said the sleep studies it relied on “drew more heavily from people in higher-income countries, where access to cooling and other heat-coping reimates for people with fewer re
The report was authored by Michelle Young, with Kristy Dahl, Raina DeFonza and Erika Freimuth serving as editors. Kelton Minor of the University of Copenhagen, whose earlier research the analysis draws on, reviewed the report. Major funding came from the Bezos Earth Fund.
This story was produced in collaboration with First Check, the health journalism vertical of DataLEADS.
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