Absolute humidity is the measure of water vapor (moisture) in the air, regardless of temperature. It is expressed as grams of moisture per cubic meter of air (g/m3) or ppm. The maximum absolute humidity of warm air at 30°C/86°F is approximately 30g of water vapor – 30g/m3. The maximum absolute humidity of cold air at 0°C/32°F is approximately 5g of water vapor – 5g/m3.