Is it true that  "It's not the heat, it's the humidity???"?
89461
Yes.\n\nThe body cools itself by evaporation of perspiration from the skin.  In dry air, perspiration evaporates rapidly causing a cooling affect but in humid air, perspiration evaporates less quickly so you don't feel as cool.  You'll feel warmer at the same temperature in a humid climate.\nhttp://en.wikipedia.org/wiki/Humidity#Effects_on_human_body\n\nIn it's simplest form, the "heat index" attempts to capture this property of perceived temperature by factoring humidity and temperature into a single value.\nhttp://en.wikipedia.org/wiki/Heat_index\n\n\nSome of the weather services such as Accuweather have devised ways of expressing the perceived temperature that include multiple factors including: "ambient temperature, wind speed, solar intensity, humidity, precipitation intentisty/type, elevation, and atmospheric pressure".  The purpose of this is to try and include all factors that might affect how we perceive temperature.\nhttp://www.accuweather.com/iwxpage/adc/help/pr_realfeel_pr.htm\nhttp://wwwa.accuweather.com/company.asp?page=about\n\nWeather.com has their "Feels Like" temperature rating which is similar.\n\n\nOf course, there are situations where it is so hot that it doesn't matter about the humidity.
902732
because our perspiration, which is the way humans cool there bodies when the temperature rises, cant evaporate. because the humidity is already  close to reaching the saturation point
438396
Ya who cares Granny!!!!!!!!!!!\nsame old Life.........And it's too hot here!!!!\nthank god i am in AC......
334098
Hot air *can* contain more moisture than cold air, but it depends on how much moisture is available for it to contain.
768153
yes, that is normal. It is just your body's reaction to the heat. Don't worry....
651341
High humidity makes the temperature seem warmer.\n\nAlso, when something condenses, as in the water in the clouds, it gives off energy often in the form of heat.
1161622
summ summ summ summertime :)\n94 today, hot as f'n hell & humid!
253562
Got to be honest. I became more and more confused about a topic that I used to understand so well with that first response. Although a lot of that is facts, it is overcomplicated at some parts and tough to get a hold on what is actually being described. No disrespect to rizzo though, I realise that everything he wrote is correct so he knows what he's talking about, I just think it would be hard for anyone else to.\n\nMaybe this description will be slightly less dizzying:\n\nAll heat is from the sun. Most of what comes from the sun is short-wave radiation, from 400nm down. Air is not heated very much from the sun, but the ground is. This is because the ground can absorb the short-wave incoming radiation, air cannot (well, only a little bit). The air is mostly heated by the longer-wave radiation that comes from the ground when it gets heated up, which heats the water molecules in the air (that's why humid regions get hotter than dry regions). \n\n*Note: Extremely dry air can be heated too, but that requires continuous exposer to sunlight. As soon as the sun is gone, it gets cold fast. Also it gets colder faster with altitude in dry regions.*\n\nAnyways. Up high, on top of being farther away from the ground, there is also less water molecules to absorb heat (and less molecules total to be heated up at all. So it absorbs less radiation. That is why it is colder. Simple. \n\nNo "adiabatic" mumbo jumbo. But adiabatic cooling is also simple. When air rises, the pressure on it decreases and it expands. The heat will be spread out over more volume, so the air will cool. This is the more complicated reason why the farther away from the ground you get, the colder the air is.\n\nAlso, there is something called an inversion. In this case, the air actually gets hotter as you go up. This happens when a warm air mass is forced up over a denser cold air mass because it is lighter. When this happens, the air is stable (it won't rise). This can result in people getting to choke on their own pollution for a couple of days because the crap they spew up in the air won't rise anymore. It's poetic.
1006187
Cold and dry, which is a good thing, since I live in Wyoming.  Very cold and dry up here.  Hot humid days kill me.
433740
Pretty darn hot! I've been living in TX most of my life and I know that most days of the week are at about 100 degrees. It does depend on where you are, though. It's worse in the panhandle (west texas).
572828
I don't know....I am from the East Coast (pennsylvania) and it is REALLY hot out today!  It's like 90 degrees with a humidity level of 35% which feels like it could be 100%!  I'm dying outside today.
169875
in the right conditions and humidity
1057414
Umm, it's the desert man, how do you think it feels?  It's hot, not humid, with an excess of sun all day long.  All because of the lack of moisture in the air to absorb the direct sunlight.  Letting it come through at full force to cause skin cancer, and bake the highways.  Did you know that at noon you can cook a hamburger on the asphalt?
1001478
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.  \n\nNow, 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.\n\nNow, 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.
15646
Humidity adds to the heat as well as the cold. \nIf the air is saturated with water, and it's also cold outside it will make it so much colder. When it's hot outside and there's high humidity it also makes it hotter, you wouldn't think so, but it feels a lot like a sauna.
1020207
That's water vapor you're seeing, not steam.
560715
If you mean on the surface, then yes. There is a big misconception about this.\n\nIt needs to be 100% relative humidity where clouds are developing NOT on the surface.\n\nThe dew point is the temperature at which saturation occurs (100% humidity). When the dew point is reached at cloud condensation level, then clouds will form & precipitation may occur.\n\nHumidity is measured in several different ways. Relative humidity is how much water vapor compared to how much it could hold at a certain temperature. This is the one we use most often.