What is the scientific explanation for air feeling sticky before rain?

Correct answer: Air near saturation slows evaporation of sweat

Correct answer: A. The human body cools itself partly by evaporating sweat from the skin. For evaporation to continue rapidly, the surrounding air must be able to accept more water vapour. Before rain, atmospheric moisture and relative humidity are often high, so the air may be close to saturation. The difference between the vapour pressure at the skin and in the surrounding air becomes smaller, and sweat evaporates more slowly. Because less evaporative cooling occurs, sweat remains on the skin and the air feels sticky or uncomfortable. B is wrong because sticky conditions involve abundant moisture, not an absence of water vapour. C is wrong because sweat does not become solid in this situation. D is wrong because air pressure does not always become zero before rain. Weather can vary, so the explanation is a common physical effect rather than an absolute rule for every rain event. Memory cue: humid air cannot accept sweat vapour easily, so the body cools less efficiently.