A strong heat wave is currently hitting much of the Midwestern and Eastern U.S., creating a dangerous mix of high temperatures and heavy humidity. This extreme weather is due to a heat “dome”, where high-pressure air traps heat and moisture over an area for several days.
This Daily news highlight shows how climate change and rising humidity are making summers more dangerous than before. Scientists and weather experts are warning people to be careful, as heat-related illnesses like heat exhaustion and heat stroke are becoming more common.
What Is Causing This Humidity?
Humidity happens when water vapor rises into the air through evaporation—the process where water changes into vapor due to heat. In the summer, hotter temperatures cause more water to evaporate from lakes, rivers, and soil.
According to Dr. James Marshall Shepherd from the University of Georgia, the more water vapor in the air, the more humid the weather becomes. Places like the eastern U.S. are naturally more humid because of their wetter climates. Warm air moving up from the Gulf of Mexico also adds moisture to the region, making the air feel heavy and sticky.
Why Does Humidity Feel So Uncomfortable?
Your body cools down by sweating. But in high humidity, the air is already filled with water vapor. This means sweat doesn’t evaporate easily from your skin, so your body stays hot.
Dr. Mary Lemcke-Stampone explains that this is due to relative humidity—a measure of how much water vapor the air holds compared to its limit. When the air is too full, sweat can’t escape from your skin, and your body can’t cool itself properly.
In drier places, like deserts, sweat evaporates faster, and people don’t feel as hot—even if the air temperature is higher. But in humid areas, your sweat stays on your body, making you feel tired, sick, and overheated.
What Is the “Wet Bulb” Effect?
The “wet bulb temperature” is the lowest temperature your body can cool down to by sweating. When both heat and humidity are very high, the human body can’t cool itself at all.
Experts say that temperatures around 95°F (35°C) with high humidity can be life-threatening. Even temperatures as low as 88°F (31°C) can cause dangerous heat stress. Symptoms include fatigue, nausea, and dizziness.
Is Humidity Getting Worse Every Year?
Yes. As the climate gets warmer, the air can hold more moisture. That means higher humidity levels in many places, especially during summer.
A study from February 2025 found that humid heat waves have grown worse over the past 40 years, especially in the eastern U.S. This is leading to longer, stronger heatwaves, and putting more people in danger.
Also, cities made of concrete and asphalt trap heat. This means even at night, the temperatures stay high, offering no break from the heat. NASA scientist Allegra LeGrande says this is a clear sign of climate change. Nights are staying hotter, making it harder for people to rest and recover from daytime heat.
How to Stay Safe – Create a Heat Action Plan
With humidity and heat rising, it’s important to prepare in advance:
- Stay hydrated – Drink lots of water throughout the day.
- Use fans and ice – They help cool your body by increasing air movement.
- Take cold showers – Underground water is cooler and helps lower body temperature.
- Know your city’s cooling centers – If you lose power or don’t have AC, these places are safe and cool.
- Check on others – Elderly people and those with health problems are more at risk, but even young, healthy people can suffer if they work outdoors in the heat.
Breaking News like this shows that extreme weather is becoming more common. As the world gets hotter and more humid, it’s important to stay informed and be ready. Taking simple steps can help prevent heat-related health problems and even save lives.
