Relative Humidity: The Hidden Reason You Can't Cool Down on a Hot Day

As large parts of India continue to experience intense heat, understanding relative humidity is crucial for public health. Relative humidity is the amount of water vapor present in the air compared to the maximum amount the air can hold at a given temperature. When relative humidity is high, the air is already close to saturation, which hampers the body's natural cooling mechanism: sweating.

Sweating cools the body as moisture evaporates from the skin, but this process is less efficient when the air is humid. The higher the relative humidity, the less you can cool yourself by sweating. This can lead to heat exhaustion, heat stroke, and other heat-related illnesses, especially during heat waves. For example, a temperature of 35°C with 70% relative humidity can feel like 45°C or more, according to heat index calculations.

Meteorologists and health officials advise monitoring both temperature and humidity levels during hot weather. Staying hydrated, avoiding outdoor activities during peak heat, and using fans or air conditioning can help mitigate risks. As climate change intensifies heat waves globally, understanding and adapting to humidity's impact on human health becomes increasingly vital.