Plain English Meaning

Two numbers reported side by side in a weather observation. The first is how warm the air is right now. The second is how cool the air would need to get before moisture starts forming. When the two numbers are close, the air is nearly wet enough to produce clouds, fog, or visible moisture.

Full Definition

A pair of values reported together in a surface aviation weather observation, expressed in degrees Celsius. Temperature is the current ambient air temperature. Dew point is the temperature to which the air must be cooled, at constant pressure and water vapor content, for it to become and water vapor to begin condensing. The smaller the spread between the two, the closer the air is to .