Dew Point Calculator
Calculate the dew point from air temperature and relative humidity with the Magnus formula, plus a comfort scale from dry to oppressive. Free and instant.
О Dew Point Calculator
The Dew Point Calculator turns an air temperature and relative humidity reading into the dew point — the temperature at which the air becomes saturated and water starts to condense. Unlike relative humidity, which moves whenever the temperature moves, the dew point is a stable measure of how much moisture the air actually holds.
It uses the Magnus formula with the widely cited Sonntag coefficients (a = 17.62, b = 243.12 °C), accurate to roughly 0.1 °C between −45 °C and 60 °C, and also reports absolute humidity in grams of water per cubic metre and the temperature-to-dew-point spread.
Meteorologists judge muggy weather by dew point rather than humidity: below 10 °C the air feels dry, above 21 °C it feels muggy, and above 24 °C it is oppressive. The tool maps your result onto that comfort scale automatically. Free and browser-based.
Как использовать Dew Point Calculator
- Choose °C or °F for the temperature input.
- Enter the current air temperature.
- Enter the relative humidity as a percentage.
- Read the dew point and where it falls on the comfort scale.
- Check the absolute humidity and the temperature−dew-point spread for the full picture.