How does humidity (or lack of humidity) affect temperature?

Answer 1

Good question. Humidity itself has a negligible affect on temperature. What it does change dramatically is the heat content of air. This means that humid air can 'carry' much more heat than dry air.

Now, humidity does change how we perceive the temperature. And its exactly for the reason above. On a rainy foggy day with the temperature at 3 or 4 deg (~38 F) have you ever noticed how cold you get? Just standing around, you begin to get fidgety just to keep warm. But on a dry night with big fluffy flakes of snow and a temperature of -3 deg, you can walk around comfortably for hours. This is simply a function of how efficiently the air takes heat from you body.

Now, if you were doused in water, the evaporation rate in the dry air would be much faster, and you would get hypothermia quicker than in the wet weather, so it gets complicated. Hope this helps.

Answer 2

You're referring to relative humidity. Air is like a sponge. It can hold water in it. It doesn't have anything to do with what the the temperature is going to be today.
The water content on a hot day does the same thing as on a cold day. It increases the heat transfer between you and the surrounding air. If it's 120 degrees in the shade and it's very dry out, the transference of heat to you is less than if the humidity were say 80%. That's why the weather guys say "it's 75 degrees out but it's going to feel like 90 with the humidity". In winter the humidity does the same thing. It increases the transfer of heat between you and the air. If it's cold with a breeze out and a high humidity, then we get wind chill factors. Things like steel or rocks or other inanimate objects are not affected by humidity. If it's 90 degrees out, they're at 90 degrees. But animals feel it hotter because of the increased physical contact.
It also restricts a persons ability to cool themselves by sweating because the air is already full of water and sweat has nowhere to go. That also increases the contact and heats you up even more.

Answer 3

Humidity does not directly affect the temperature of the air.

The significant affect is on the temperature of things that use the evaporation of water for cooling(like people, and industrial cooling towers, and swamp coolers, and most mammals).

The lower the relative humidity, the "thirstier" the air is and the more quickly and easily water will evaporate. Evaporating water pulls heat from its surrounding to complete the evaporation. Animals sweat in order to cool by evaporation. If the humidity is very high, the sweating will make you wet but will provide little or no cooling. That is why days with higher humidity make us hotter, even though the air is not hotter. Without cooling, warm blooded animals just get hotter and hotter.

Answer 4

i think so. It is said in the song its Raining Men by Geri Halliwell.

"Humidity's rising
Barometer's getting low"

-the higher the humidity, the cooler the temperature. Why? Coz its gonna rain?! I mean, there is no such thing as hot rain.