Quick answer: A July 2026 Climate Central analysis estimates that the average person lost nearly 56 hours of sleep a year to high night-time temperatures in 2020 to 2025, and that about 6 hours of that (roughly 10%) is attributable to climate change. Spread across a year, 56 hours is about 9 minutes a night on average, but the loss is concentrated on the hottest nights, so a few very hot nights matter far more than the average suggests.
What the report says
Climate Central analyzed 1,338 cities with populations over 500,000, plus 253 US cities, using ERA5 daily minimum temperature data and its Climate Shift Index, with counterfactual temperatures from a 24-model CMIP6 ensemble. The headline findings:
- Global average: nearly 56 hours of sleep lost per year to high ambient temperatures (2020 to 2025), about 6 hours of it attributable to climate change
- Most affected: cities in Saudi Arabia, Oman and the UAE, at 12 to 16 hours a year attributable to climate change
- United States: about 4 hours a year on average from climate change, with Arizona, California, Florida and Nevada at 7 to 9 hours
- Trend: climate-attributable sleep loss has at least doubled since the early 1970s in 1,335 of the 1,338 cities
Source: Climate Central, “Climate Change is Costing People Sleep” (July 15, 2026). These figures are modeled from temperature data and a published relationship between temperature and sleep, not measured directly in each city.
The research underneath
The temperature-to-sleep relationship comes from Minor et al., “Rising temperatures erode human sleep globally,” published in One Earth in 2022. The team used sleep-tracking wristband data, over 7 million sleep records from 47,628 people in 68 countries, paired with weather data. Their abstract reports that:
- Warmer temperatures shorten sleep mainly by delaying when people fall asleep
- Lower-income countries, older adults and women lost more sleep per degree of warming
- People in already hot places lost a similar amount per degree, which suggests limited adaptation
- Under high-emissions warming scenarios, the authors projected about 58 hours (range 52.7 to 65.2) of sleep lost per person per year by 2099
A ScienceDaily summary of the paper adds that on very warm nights above 30 C (86 F), people lost about 14 minutes of sleep on average, and that the study had no data on air conditioning access, which may help explain why wealthier countries showed less loss.
What this means for you
An average of about 9 minutes a night sounds trivial, but averages hide the shape of the problem. Sleep is lost in chunks on the hottest nights, which are the nights when a bedroom that stays warm makes it hard to fall asleep. The practical target is those nights.
What helps on hot nights
We have detailed guides for each of these, so this is the short version.
- Cool the room and your bed before you lie down. See How to Sleep Cool During a Heatwave (Without AC) and How to Stay Cool While Sleeping at Night.
- Choose breathable bedding. Our cooling bedding guide and cooling pillow guide cover what to look for.
- If your mattress sleeps hot, that matters most. See Best Mattress for Hot Sleepers.
- Plan for outages and heat waves. When the Grid Can’t Keep Up covers what to do when cooling fails.
- If you are older or have a health condition, follow local public health heat guidance rather than relying on sleep tips alone.
Common Mistakes
- Reading “56 hours” as an even nightly loss
- Assuming a fan alone is enough on the hottest nights
- Treating this as only a future problem, when the report says the loss has already doubled since the early 1970s
FAQ
Does 56 hours mean I lose sleep every night?
No. It is an annual total across many nights, about 9 minutes a night on average, and it is concentrated on hot nights.
Who loses the most sleep to heat?
In the underlying research, lower-income countries, older adults and women lost more sleep per degree of warming, and cities in the Middle East had the highest climate-attributable losses in the Climate Central report.
Is the 56 hours measured or modeled?
Modeled. It combines observed temperatures with a temperature-sleep relationship drawn from wearable data.
Key Takeaways
Hot nights are already costing people sleep, and the total has grown since the 1970s. The average hides a concentrated loss on the hottest nights, which is where cooling your bedroom and bed does the most good.
About this article
Written by the Sleep Fixes editorial team. We’re not medical professionals. We research each topic against primary sources and say plainly when a figure is modeled or comes from a secondary summary. This article draws on Climate Central’s July 2026 analysis and the 2022 One Earth study behind it. The 9-minutes-a-night figure is our own arithmetic (56 hours divided by 365 nights). It is not medical advice.