Why Humid Days Are Warm and Sticky?


Many weather experts insist on being absolutely accurate in defining terms. For most people though, the simpler the explanation about humidity the better. In simple terms, humidity is a measure of the amount of water vapor in the air. The truth is that much of the earth’s surface is covered with water, millions of cubic miles of it. Only a very small fraction of that is water vapor. The amount of water vapor however at any given time is a valuable tool in weather forecasting.

How did water vapor get into the air anyway? Part of understanding humidity is also knowing the basic concept of evaporation. When there is sufficient thermal energy, kinetic energy is transferred to water molecules on earth, thereby allowing them to break free from their liquid form and evaporate. More water therefore tends to rise up on hot days simply because there is substantial thermal energy.

Once up there, a certain saturation point has to be reached for precipitation to be possible. In other words, when water vapor is too much at a certain temperature, rain might fall. Different temperatures come with different saturation points.

One term that is vital to understanding humidity is relative humidity. If you often listen to weather reports, you are likely to hear this term. Relative humidity is simply the amount of current water vapor compared to the amount needed for saturation to occur at a certain temperature. Relative humidity is expressed in percentages and is again a useful tool when predicting the weather. For rain to occur, relative humidity should be at 100%.

This is all well and good for weather forecasters and specialists. Average individuals though would be more likely to wonder about the connection between high humidity levels and body temperatures. When conditions are humid, we often feel warm and uncomfortable. This is because body temperature is regulated by perspiration. When the saturation point has been reached, human sweat cannot effectively evaporate, thereby leading to the familiar feelings of discomfort on a humid day. In some cases, we may even feel languid or lazy on a humid day. This happens when the environment is too warm for the skin to release heat.

This fact can also now help us understand why we need humidifiers and dehumidifiers. It is estimated that humidity should be at about 30% to 60% to keep comfortable. The mid point between this range is the ideal figure. In many offices therefore, air conditioning set correctly is important to ensure maximum comfort and performance.

Humidity need not be rocket science. Although it is really quite complicated, it is enough to know what it is and why it is important to know about it.

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