Why does it takes so long for a track to dry? Why does humid weather make track drying take even longer? Air is a mix of gas molecules: mostly (78%) nitrogen, about 21% oxygen, the rest misc. gases. The composition is pretty uniform with the exception of how much water is in the air. The absolute humidity is the amount of water in some chosen volume of air, for example, how much water vapor is in one cubic meter of air. Air can only hold so much water vapor and that amount depends on the temperature and pressure. Dry air would be no ounces of water in a cubic foot of air. If the vapor is saturated at 30 degrees centigrade (86 degrees Fahrenheit), then the amount of water could be up to three one-hundredths of an ounce of water per cubic foot. [...]