01 · If
Average warming can look small and abstract.
The grey line shows observed U.S. average temperature from 2000 to 2020, and the colored lines show CMIP6 futures through 2100. On a chart, a few degrees can look like a slow, abstract shift.
02 · But
Turning average warming into calendar days.
The annual average trend becomes more concrete when we count extra very hot summer days, defined as days with daily highs above 35°C.
03 · But
Extra very hot days do not land evenly across states.
Under high emissions, compare your hometown state with the state projected to gain the most baseline-aligned 5-year average summer very hot days by 2100.
04 · Therefore
Where do very hot days affect the most people?.
Extra very hot days matter more when more people are exposed. The next view combines extra very hot summer days with projected population.
05 · Exposure
Carry your selected state into exposure.
Exposure are built from extra very hot days and projected population, then compared with the national benchmark.
06 · U.S. comparison
By 2100, national heat exposure increases sharply.
Each sun represents the same amount of heat exposure. One exposure-day means one person experiencing one additional 35°C+ summer day.
Impact
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Daily impact of exposures
We turned warming into very hot days, and very hot days into exposure. Now follow the heat into daily life — from who is exposed, to how it harms the body, to where it shows up.
01 · Population exposure
Hot days × people = exposure
A very hot summer day is any day above 35°C . Multiply projected very hot days by projected state population and we get person-days of exposure. Sustained increases drive excess mortality, lower productivity, and overloaded health services — hitting the elderly, outdoor workers, and low-income families hardest.
02 · Older adults
Age 65+ are most at risk
Older adults are at much higher risk from extreme heat. Their bodies cool down less efficiently through sweating and circulation, and this is made worse by chronic diseases and medications. As a result, older adults experience more heat-related illness and death than any other age group, mostly from heart complications.
03 · Vulnerable populations
Some people can't just stay inside
Air conditioning and staying indoors are common solutions for extreme hot days, but some groups can't escape exposure. Outdoor workers in construction, agriculture, and delivery endure long hours while generating extra body heat. Low-income communities are more exposed too, with limited AC access and poorer housing.
04 · Humidity vs. hot-dry heat
Not all heat harms the same way
The body cools itself mainly through sweating. When humidity is high, sweat cannot evaporate easily, so heat gets trapped in the body and even moderate temperatures become dangerous. In dry heat, sweat evaporates well and the body can cool down, but people lose water quickly and get dehydrated. Humid heat is the most dangerous because it stops the body's main way of cooling itself.
05 · Sleep
Hot nights cut sleep by ~14 minutes
On very warm nights above 30°C, sleep declines by about 14 minutes. More frequent hot nights make people fall asleep later and wake up earlier, compressing the sleep period and reducing sleep quality.
06 · Learning
A hotter school year lowers learning by ~1%
Without air conditioning, a 0.56°C hotter school year reduces that year's learning by about 1%. Hot school days also disproportionately affect minority students, accounting for roughly 5% of the racial achievement gap.
07 · Cooling cost
Summer electricity use rises ~3%
EIA's 2024 forecast expected a 5% rise in cooling degree days to increase average U.S. household summer electricity use by about 3% — a recurring cost that lands hardest on families who can least afford it.
08 · Emergency room visits
Heat pushes up ER visits across categories
Hotter temperatures can increase emergency department visits for injuries, mental health issues, poisonings, and other heat-sensitive conditions, adding pressure to a healthcare system already stretched thin.
Takeaway
A few degrees of warming might not feel like much. But the real risk shows up in daily life.
Under high emissions, that small average increase can mean many more days above 35°C. And when millions of people live through those extra hot days, climate change is no longer just a number—it becomes exposure, stress, cost, and health risk in everyday life.
07 · Explore
Explore states and climate metrics yourself.
Use the controls to switch scenario, year, metric, and exposure bubbles. Hover states to preview values, then click a state to carry it into the local detail section.