clouds in vapour form can remain in vapour form even at temperature below 100 degree, why?
438791
altitude.....higher altitude means lower air pressure.  Liquids, water included, vaporizes at lower temp when pressure lowers.  (a glass of water will boil at room temp in a vaccumn)
43357
If the air in a room is saturated, the relative humidity for the given temperature is 100%.  If you boiled water in the room, mooisture would have to condense elsewhere in the room.  If you condense moisture from the air instead, the relative humidity would become less than 100%, depending on how much moisture you removed from the air.  If you cooled the room instead, the relative humidity would remain 100% but moisture would have to condense on the coolest surface(s) in the room.  If you heated the room instead, the relative humidity would become less than 100% (provided there is no water in the room to evaporate).  Saturation is a limit on the amount of moisture a room can hold at a given temperature.  It covers a lot of bases.
350316
A reading of 100 percent relative humidity means that the air is totally saturated with water vapor and cannot hold any more, creating the possibility of rain. This doesn't mean that the relative humidity must be 100 percent in order for it to rain -- it must be 100 percent where the clouds are forming, but the relative humidity near the ground could be much less.\n\nHumans are very sensitive to humidity, as the skin relies on the air to get rid of moisture. The process of sweating is your body's attempt to keep cool and maintain its current temperature. If the air is at 100-percent relative humidity, sweat will not evaporate into the air. As a result, we feel much hotter than the actual temperature when the relative humidity is high. If the relative humidity is low, we can feel much cooler than the actual temperature because our sweat evaporates easily, cooling us off.
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.
348720
(m)\n\nThe amount of moisture air can retain is determined by its temperature and, to a lesser extent, its pressure. Any sufficient drop in temperature or increase in pressure will cause moisture to condense out of the air. \n\n \n\n Relative humidity is the amount of moisture that is present in the air, compared to the total amount the air could hold at a certain temperature. For example: One cubic foot of air at 80°F, 27°C can hold about 12 grains of moisture.\n\nIf it is holding all 12 grains, it is said to be at 100% relative humidity or saturated. If that same cubic foot of air is holding only 6 grains of moisture, it is at 50% relative humidity.\n  \n Saturation point is the point at which air is holding all the water vapor it can (100% relative humidity). If we added more water vapor to saturated air, the water vapor would condense into a liquid.\n\nRemember that a drop in temperature or increase in pressure will cause moisture to condense out of air that is saturated.\n \n\n  Condensation is the changing of water vapor into a liquid.\n\nDew point is the temperature at which water vapor in the air condenses into a liquid.\n \nPressure dew point is more meaningful because it indicates, at a given pressure, the temperature at which condensate forms in the compressed air lines.
973898
That is a fantastic question.\nIt is a matter of humidity. The cold weather\nthat allows snow means the air is not humid\nenough to allow an electric current to travel\n(along the water vapor in the air) over the differently\ncharged clouds and sky. People who say temp are\nsort of right, but it is the low temp that leads to the low\nhumidity that causes the "problem".\n\nThanks for asking such a good question.
913566
the clouds from the sky helps regulate the temperatures.
769934
It's the actual temperature with humidity, wind chill factor (if applicable), dew point and other conditions taken into consideration. There's actually a mathematical equation to figure it out but it may be hard to find since the calculations are done by computers these days.
1112416
Water molecules in the air are continually shifting from liquid to vapor. As the Brownian motion and swirling air currents or breezes are moving them around. \n   Thus some of the water at 100 % humidity will be condensing on cooler surfaces while others are evaporating from warmer surfaces eg. your skin.\n   P.S. Your question didn't say but I hope you are standing under a umbrella or something cause at 100% humidity it's likely to be raining. \n\n  Also humidity is relative to air temperature so if the sun is shining during this sun shower, the true quantity of vapor in the air may continue to rise, while humidity actually falls.\n  Nature is truly a conundrum, and even the best super computers, and weather models fail to predict what the weather will do.\n So don't strain your brain.
635522
It depends on the liquid AND the pressure. 100C is for water at atmospheric pressure.
818482
A cloud is a visible mass of condensed droplets or frozen crystals suspended in the atmosphere above the surface of the Earth or another planetary body. The branch of meteorology in which clouds are studied is nephology.\n\nOn Earth, the condensing substance is water vapor, which forms small droplets of water or ice crystals, typically 0.01 mm in diameter. When surrounded with billions of other droplets or crystals, they are visible as clouds. Dense deep clouds exhibit a high reflectance (70% to 95%) throughout the visible range of wavelengths: they thus appear white, at least from the top. Cloud droplets tend to scatter light very efficiently, so that the intensity of the solar radiation decreases with depth into the cloud, hence the grey or even sometimes dark appearance of the clouds at their base. Thin clouds may appear to have acquired the color of their environment or background, and clouds illuminated by non-white light, such as during sunrise or sunset, may be colored accordingly. In the near-infrared range, however, clouds would appear very dark because the water that constitutes the cloud droplets strongly absorbs solar radiation at these wavelengths.\n\nCloud formation and properties\nClouds form when the invisible water vapor in the air condenses into visible water droplets or ice crystals. This can happen in three ways:\n\n1. The air is cooled below its saturation point. This happens when the air comes in contact with a cold surface or a surface that is cooling by radiation, or the air is cooled by adiabatic expansion (rising). This can happen:\n* along warm and cold fronts (frontal lift)\n* where air flows up the side of a mountain and cools as it rises higher into the atmosphere (orographic lift)\n* by the convection caused by the warming of a surface by insolation (diurnal heating)\n* when warm air blows over a colder surface such as a cool body of water.\n\n2. Clouds can be formed when two air masses below saturation point mix. Examples are breath on a cold day, aircraft contrails and Arctic sea smoke.\n\n3. The air stays the same temperature but absorbs more water vapor into it until it reaches saturation point.\n\nThe water in a typical cloud can have a mass of up to several million tonnes. However, the volume of a cloud is correspondingly high, and the net density of the relatively warm air holding the droplets is low enough that air currents below and within the cloud are capable of keeping it suspended. As well, conditions inside a cloud are not static: water droplets are constantly forming and re-evaporating. A typical cloud droplet has a radius on the order of 1 x 10-5 m and a terminal velocity of about 1-2 cm/s. This gives these droplets plenty of time to re-evaporate as they fall into the warmer air beneath the cloud.\nCumulonimbus cloud\nEnlarge\nCumulonimbus cloud\n\nMost water droplets are formed when water vapor condenses around a condensation nucleus, a tiny particle of smoke, dust, ash, or salt. In supersaturated conditions, water droplets may act as condensation nuclei.\n\nWater droplets large enough to fall to the ground are produced in two ways. The most important means is through the Bergeron Process, theorized by Tor Bergeron, in which supercooled water droplets and ice crystals in a cloud interact to produce the rapid growth of ice crystals; these crystals precipitate from the cloud and melt as they fall. This process typically takes place in clouds with tops cooler than -15°C. The second most important process is the collision and wake capture process, occurring in clouds with warmer tops, in which the collision of rising and falling water droplets produces larger and larger droplets, which are eventually heavy enough to overcome air currents in the cloud and the updraft beneath it and fall as rain. As a droplet falls through the smaller droplets which surround it, it produces a "wake" which draws some of the smaller droplets into collisions, perpetuating the process. This meth
279806
The air's ability to hold water is a factor of temperature.  That's why humidity is referred to as "Relative Humidity" (its relative to the temperature).  So as the air cools at night, it has less ability to hold water.  What may have been 60% humidity during the day, may end up causing rain during the night.
756259
Clouds are made of miniscule water droplets.  When you consider how enormous clouds are (in volume), all those water droplets can add up to a very high weight.  Think how heavy a glass of water is.  Now let's try to extrapolate how much vapor that will make -- perhaps 5-10 cubic feet?  Now multiply that number of glasses by how many cubic feet of space a cloud takes up...\n\n<quote>\n\n"The water in a typical cloud can have a mass of up to several million tonnes. However, the volume of a cloud is correspondingly high, and the net density of the relatively warm air holding the droplets is low enough that air currents below and within the cloud are capable of keeping it suspended. As well, conditions inside a cloud are not static: water droplets are constantly forming and re-evaporating. A typical cloud droplet has a radius on the order of 1 x 10-5 m and a terminal velocity of about 1-2 cm/s. This gives these droplets plenty of time to re-evaporate as they fall into the warmer air beneath the cloud."\n\n</quote>
490142
Air temp would be at or below dewpoint. When the air is cooled below its dewpoint, water condenses out of the air, which reduces the air's dewpoint. Thus the dewpoint tends to follow the air temperature downwards. When in perfect equilibrium, air temp would be equal to the dewpoint. If the air temp is above the dewpoint the condensation would re-evaporate and the fog would clear.\nAnswerer 3: If you see fog, the water vapor HAS condensed. It just hasn't settled out yet.\nAnswerer 4: Condensation is a simple change of state, not a chemical reaction.
704548
There is no way to answer this without knowing what the dewpoint and RH is.  Humidity is not necessarily a function of temperature even though it might seem as such when one thinks about the tropics.  You have to have more than what you've got here in order to answer.
33298
3 things r neede for cloud formation...cooling of air, presence of water vapour (relative humidity shud be close to 100%), and condensation nuclei( like dust particles).\ndunno who found it, sorry
388380
None of the above.  The amount of moisture in an air mass is relative.  "Very little moisture" tells us nothing about the temperature, dew point or stability of an air mass which are the determining factors for cloud formation.