More moisture in the lower atmosphere means perspiration works less effectively and can stymie bodily recovery with warmer nighttime temperatures.

The heat index is a measure of how hot it really feels on your body when relative humidity is factored in with the actual air temperature.

High heat alone is a risk to humans, but heat and humidity together make an especially dangerous combination. Humidity has to do with the concentration of water vapor in the air, that cloying ...

The humidity also plays a role, making it feel hotter than the actual temperature, called the heat index. This is calculated by using the temperature versus the relative humidity. For example ...

Humidity impairs the body’s ability to release heat, more so in older people, said Dr. Rene Roberts, family medicine physician at Oak Street Health. “As we age, the body changes.