What Is Relative Humidity? | Relative Humidity Explained?

Relative humidity is how much moisture is in the air compared to how much it can hold.

Imagine you have a glass of water on your table. When you leave it out, eventually some of that water turns into vapor and floats up into the air, like when you see steam rising from a hot cup of soup. Now, if that glass is full of water, more vapor can go into the air before the air feels "full" of moisture. But if the glass is only half-full, less vapor can go in before the air feels full.

Relative humidity is like that glass, it shows how much water vapor is in the air compared to how much it could hold. If the air is holding all the water vapor it can, that’s 100% relative humidity, and you might feel sticky or even see fog or clouds forming.

If the air has less moisture than it can hold, say it's only halfway full, then the relative humidity is lower, like 50%. That means the air could still take in more vapor before feeling "full."

So when we talk about relative humidity, we're just talking about how much "water space" the air has used up, like a glass that’s either full or half-full of water.