Meaning & use
relative humidity
Last updated
Meaning
noununcountable
The amount of water vapor in the air shown as a percentage of the most the air could hold at that temperature.
Grammar: Used without 'a' or a plural: Relative humidity was 80 percent.
Patterns
- high relative humidity
- low relative humidity
- relative humidity of something
The weather report said the relative humidity would reach 90 percent by evening.
Plants lose water faster when the relative humidity is low.
A relative humidity of 100 percent means the air is completely full of moisture.
Common combinations
- high relative humidity
- High relative humidity makes hot days feel much worse.
- low relative humidity
- Low relative humidity can dry out your skin and throat.
- measure relative humidity
- Scientists measure relative humidity with a device called a hygrometer.
- relative humidity level
- Keep the relative humidity level between 40 and 60 percent indoors.
Synonyms and how they differ
- humidity
- This is the general word for moisture in the air; 'relative humidity' is the specific percentage measure.
Opposites
Word family
- humid adjective
- Describing air or weather that contains a lot of water vapor.
- humidity noun
- The general term for water vapor in the air.
- relatively adverb
- In comparison with something else; used in many contexts, not just weather.
Commonly confused: relative humidity or absolute humidity?
relative humidity vs absolute humidity
Absolute humidity measures the actual mass of water in a volume of air; relative humidity compares that amount to the maximum possible at the same temperature.
Practice
The weather app says the relative humidity is 85 percent. What does this mean?
Choose one answer.
Relative humidity is a percentage comparing current water vapor to the maximum possible at that temperature. Option An is wrong because air is mostly nitrogen and oxygen, not water. Option C confuses humidity with rainfall, and option D confuses it with temperature.
Make it your own
Write a sentence using “relative humidity”, then check it and compare it with the examples above.