As the barometric pressure and temperature decrease why does the humidity increase?

Question

As the barometric pressure and temperature decrease why does the humidity increase?

Answer 1

In simpler words as the temperature decreases the air contracts.. so the same amount of moisture that was present in a larger mass of air is now present in a smaller mass and that is the reason why the humidity increases..

Answer 2

I don't know about Pressure but when temperature decreases and the same amount of moisture stays in the air the percent relative humidity has to increase. Since Colder air cannot hold as much moisture as warm air it becomes more saturated. So there is not actually more moisture just a higher percent of the air is moisture. Dew Point temperature is the actual amount of moisture in the air. If the air temperature falls to the dew point temp fog is formed because the air cannot hold anymore moisture and it is completely saturated or 100% relative Humidity.



If the air temp is 45 and dew point is 39 Humidity is less than 100%



If air temp falls to 39 in same air mass Humidity is 100%