rain, flooding and clouds
The ratio of water vapor in a volume of air relative to how much water vapor that volume of air is capable of holding is called relative humidity. It is expressed as a percentage and provides insight into how close the air is to being saturated with water vapor.
It may condense into clouds, or into precipitation, because cooler air cannot hold as much water vapor as warmer air.
The amount of actual water vapor in the air to how much saturated water vapor could be in the air.
cold air
The amount of water vapor that warm air can hold, known as its saturation water vapor pressure, increases exponentially with temperature. Warmer air can hold more water vapor than cooler air before reaching saturation.
Water in a container consists of liquid in the container and water vapor above the container. As the air passes, it carries off the water vapor above the water and the water in the container replenishes it. Moving air blows water vapor away much faster than still air. As a result, a plate with water in it will dry faster if air is blowing on it than a plate will if no air is blowing on it.
Water vapor in the air is water in the form of a gas.
Humidity (relative) is the amount of water vapor in the air, expressed as a percentage of the maximum amount that the air could hold at the given temperature; the ratio of the actual water vapor pressure to the saturation vapor pressure. So pretty much the air is moist and heavy.
The water vapor content in the air, also known as humidity, can vary greatly depending on location, temperature, and weather conditions. On average, the water vapor content in the Earth's atmosphere is around 1% to 4%.
The property that primarily controls how much water can be present as a gas is temperature, which influences the water vapor pressure in the air. Warmer air can hold more water vapor compared to cooler air.
The amount of water vapor in the air, known as humidity, can vary depending on location and weather conditions. On average, the air contains about 1-3 water vapor.
Relative Humidity (RH), is how much water vapor is in the air at a certain time. Humidity, in my opinion, is just another way of saying how much water vapor is in the air.