What is the dew point?
The dew point is the temperature at which water vapor in the air can no longer stay as vapor and begins to condense into dew (liquid water). When the air temperature drops below the dew point, water vapor condenses, forming dew on grass at dawn or fog in the air.
How is it calculated?
This calculator uses the widely used Magnus formula in meteorology to approximate the dew point temperature from the temperature and relative humidity you enter.
Using dew point to judge comfort
- Dew point 10Β°C or below: dry and comfortable
- Dew point 10β16Β°C: comfortable
- Dew point 16β20Β°C: somewhat humid
- Dew point 20Β°C or above: very humid and uncomfortable
Dew point is often used because it reflects how humid the air actually feels more intuitively than relative humidity alone.
Check the discomfort index too
Curious how hot and humid conditions actually feel? Try the Discomfort Index Calculator as well.
Frequently Asked Questions
Can the dew point be higher than the air temperature?
No β the dew point is theoretically always lower than or equal to the current air temperature, and the two become exactly equal when relative humidity reaches 100%.
How is dew point different from relative humidity?
Relative humidity is expressed as a percentage relative to temperature, so the same humidity can feel different depending on the temperature. Dew point represents the absolute amount of water vapor as a temperature value, making it more useful for comparing humidity across seasons or temperatures.