Bangladesh now faces 200 dangerous humid heat days a year as climate change intensifies global heat risks, according to a new Climate Central analysis.
The analysis said Bangladesh is emerging as one of the countries facing some of the most persistent exposure to hazardous heat and humidity conditions.
While dangerous humid heat has increased across tropical regions, including South and Southeast Asia, Bangladesh's dense population, large outdoor workforce, rapid urbanization and limited access to cooling make the country particularly vulnerable to its impacts, according to the analysis.
The impacts are already evident across Bangladesh's major cities.
Khulna now experiences an average of 224 dangerous humid heat days each year, while the capital city Dhaka, home to more than 20 million people, now experiences an average of 210 dangerous humid heat days each year, with 25 days annually added by climate change.
In Chittagong, Bangladesh's one of the major commercial hubs and major coastal city, residents experience an average of 211 dangerous humid heat days per year, while climate change contributes an additional 36 days annually which is more than a full month of dangerous humid heat that would not have occurred without global warming.
Dangerous humid heat days have more than doubled worldwide since the 1970s due to human-caused climate change.
“Extreme heat and humidity driven by climate change are increasingly affecting children's health. We are seeing more cases of cough, breathing difficulties, and asthma-related illnesses among children,” said Dr Shimul Mazumder, senior consultant (Child Health), Comilla General Hospital.
He said compared to previous years, asthma and related respiratory conditions have risen by nearly 70%, highlighting the growing health risks posed by extreme heat.
The health impacts extend beyond heat-related illnesses. According to physicians, extreme heat is also contributing to a rise in waterborne diseases as people struggle to stay hydrated during prolonged hot weather.
"Rising heatwaves are increasing the risk of waterborne diseases. As people consume more water during hot weather, many rely on unsafe sources, leading to higher cases of diarrhoea, typhoid, and jaundice,” said Dr Rashedul Hasan, associate professor, Department of Medicine, Green Life Medical College and Hospital.
As Bangladesh continues to face rising temperatures and increasingly humid conditions, the findings underscore the need for stronger heat-health preparedness, workplace protections, urban cooling measures and greater investment in climate-resilient public health systems.
Globally, dangerous humid heat days increased from an average of 10 days per year in the 1970s to 23 days annually during 2016-2025.
The analysis found that nearly two-thirds (64%) of dangerous humid heat days worldwide since 1970 can be attributed to climate change, making it the primary driver of increasingly dangerous heat-humidity conditions across the planet.
In Bangladesh, where high temperatures frequently combine with intense humidity, dangerous humid heat is already a common part of daily life.
The country experienced an average of 200 dangerous humid heat days per year during 2016-2025, up from 175 days annually in the 1970s.
The study found that climate change is now adding around 30 dangerous humid heat days to Bangladesh each year, equivalent to an additional month of potentially hazardous conditions.
In the 1970s, climate change contributed only five such days annually. The share of dangerous humid heat linked to climate change has increased fivefold, from 3% in the 1970s to 15% during the last decade.
The findings highlight how climate change is transforming heat exposure around the world.
Unlike dry heat, humid heat prevents the body from cooling effectively through sweating. As humidity rises, the risk of dehydration, heat exhaustion, heat stroke, cardiovascular stress and other heat-related illnesses increases substantially.
Health experts warn that older adults, children, pregnant women, outdoor workers and people with underlying medical conditions face the greatest risks.
The global analysis comes as extreme heat is becoming one of the deadliest consequences of climate change.
More than a quarter-million people worldwide have died from extreme heat since 2000, and researchers warn that rising humidity is making heat increasingly dangerous by pushing conditions closer to the limits of what the human body can safely tolerate.