Relative humidity is affected primarily by temperature and the amount of moisture in the air.
Here's a breakdown:
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Temperature: Warm air can hold more moisture than cold air. Therefore, if the amount of moisture in the air remains constant, relative humidity decreases as temperature increases, and relative humidity increases as temperature decreases. Think of it as a percentage of how saturated the air could be.
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Moisture Content: The more water vapor present in the air (absolute humidity or specific humidity), the higher the relative humidity, assuming the temperature remains constant. Adding moisture increases the percentage of saturation.
In simpler terms:
Imagine a glass. Relative humidity is how full the glass is with water (moisture) compared to how much it could hold.
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If you heat the glass (increase temperature), the glass becomes bigger (can hold more), so the same amount of water appears to fill it less (lower relative humidity).
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If you add more water to the glass (increase moisture), the glass becomes more full (higher relative humidity).
Therefore, a lower temperature and a higher moisture content lead to a higher relative humidity. A higher temperature and lower moisture content result in a lower relative humidity.
