What causes humidity?
546937
water vapors are always present in athmosphere. Remember that when you boil water and it reaches 100 dgs Celsius, it begins to evaporate, producing vapors. So, the opposite happens when the temperature drops down, water vapors turn liquid and, if it is cold, I mean under 0 dgs, they turn into ice and fall down on earth as snow flakes. This is called Nature's Water Circuit ;)
585097
Moisture forms on things, whether it's morning dew, or heavy fog, or rain.  If there isn't enough moisture for rain, dew forms.
95373
maybe a drop in the humidity level or a change of wardrobe
550764
If this is a constant problem then buy a humidifier. Static electricity is less likely to happen if the air in your house is not so dry.
131647
dry air, hemmorrage, a hard right, or others. If it keeps happenin' see a doctor.
427838
Noun: relative humidity. The ratio of the amount of water in the air at a give temperature to the maximum amount it could hold at that temperature; expressed as a percentage\n\nRelative humidity is the ratio of the current vapor pressure of water in any gas (especially air), known as the absolute vapor pressure (AVP), to the equilibrium vapor pressure or saturation vapor pressure (SVP), at which the gas is called saturated at the current temperature, expressed as a percentage.\n\nEquivalently, it is the ratio of the mass of water per unit volume of gas and the mass of water per unit volume of a saturated gas.
579075
Absolute humidity is the amount of water in a given volume of air.\n\nRelative humidity is the amount of water in a given volume of air relative to the maximum amount that could be there without condensation occurring.
479744
You don't, it just doesn't evaporate like it would in non-humid conditions.  Its all about the movement of water, and if the air is already very dense with water particles (ie. humidity) then the liquid on your skin is less inclined to enter the air.  But in very dry conditions, the water on your skin evaporates quickly and this cools you down.
397516
The humidity/heat make breathing difficult, but also if you are on city water, alot of chemicals are added to kill bacteria and diseases in the water-these chemicals tend to cling to moisture like vapour particles which you then breathe in.  Maybe it was all a bit much for you- or you are developing a sensitivity-we are bombarded with toxins in the air 24/7.  Mention it next time you are at the doctors, go to the hospital if it happens and doesn't subside.
709288
the air is already saturated with moisture and cant hold much more, so the sweat on your skin stays instead of evaporating which is a natural cooling process
576407
1. Heat\n2. Lower the humidity\n3. Air movement\n4. Lower barometric pressure\n5. Some combination of above
602307
add moisture to a room
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.
30608
Clouds are formed when warm moisture laden air is forced upwards either by a physical obstruction such as a hill/mountain or by being heated by the ground/sun.\nAs it rises it cools, and cold air can hold less moisture than warm air, so the vapour condenses out into droplets that form our clouds.\n\nFog is caused when moisture laden air is cooled by contact with the ground or water, it gets colder and colder until any moisture condenses out.  Fog forms as a layer as the air above it tends to be warmer due to rflected heat from the sun and also becauseof the lack of wind to stir the two layers together.  This is often referred to as an inversion.
1016720
moisture is a by-product of combustion, as combustion is really rapid oxidation (burning).  this is why you see moisture dripping off someone's vehicle tailpipe before it heats up and evaporates.  \n\nthe aeresolized water at the rocket-competition you describe refracts the sunlight if the sun is behind you, and the launch ocurred in front, producing the rainbow.
608753
Because the humidity levels are up, causing more moisture in the air before the actual rain.
620707
As air gets warmer it's able to contain more water vapor.  An easy way to illustrate this is in a steamy kitchen or bathroom where you'll see that condensation forms on the coldest surfaces such as windows, mirrors, tiles etc.\n\nWhen the amount of water vapor in the air reaches it's maximum point the air is described as being saturated (saturation vapor pressure or SVP for short).  SVP is therefore reached more quickly when the air is cooler.\n\nWhen air reaches SVP it has to deposit the excess moisture which it does as dew or condensation and the point at which this occurs is called the dew point.  The colder the temperature the lower the dew point which helps explains the cool mornings when there's dew on the grass.\n\nHumidity is a measure of the amount of water vapor that's present in the air and is measured as a percentage of the maximum possible.  So a Relative Humidity (or RH) or say 60%, means that the air contains 60% of the maximum possible water vapor.  As mentioned, the amount of water vapor possible increases with temperature and so RH is affected by temperature.  An RH of 80% in a hot tropical climate is going to feel much damper and humid than an RH of 80% in a cooler climate.