For example, I spend time in Little Rock and San Clemente. LR is always far more humid, to the point it’s not even relatable. But SC seems to generally have a higher relative humidity. Right now it is 84% in SC and 54% in LR. Is this because the air in SC somehow cannot hold as much humidity as the air in LR?
In: 6
They don’t. It’s just unusually humid in southern California right now.
RH does depend on temperature, so cooler places can be dryer with higher RH. But SoCal isn’t very cool.
In Little Rock, it is now 31C and a relative humidity of 47%. In San Clemente, it is 16C and 84% relative humidity.
The amount of water air can hold depend on the temperate the warmer it is the more water it can hold. The relative humidity is the percentage of max at the current temperature
If you use [https://www.omnicalculator.com/physics/absolute-humidity](https://www.omnicalculator.com/physics/absolute-humidity) you can calculate absolute humidity.
47% at 31C is 15.1g/m^3, 84% at 16C is 11.5g/m^3 so there is more water in the air in Little Rock even if the relative humidity is lower.
If you cool down air the relative humidity increase so 47% at 31C is equal to 100% at 18C. So if you get the moist air into a cold enviorment it will start to condensate to liquid water
Relative humidity has always been a terrible way to describe how much moisture is in the air. The capacity to hold moisture increases exponentially as temperature rises. This means there can be days where the amount of moisture is completely unchanged, but the relative humidity will go from 100% at dawn to 30% by peak daytime heating.
For all practical purposes, absolute humidity is the value people should use. But absolute humidity is a measure that is never available. Therefore we need to use absolute humidity’s non-linear cousin – dewpoint. If you are a human being – dewpoint is always the value you should use to describe how humid it is. A dewpoint of 75F is always really humid, and a dewpoint of 30F is always really dry, regardless of temperature.
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