Dew Point Calculator
Find the dew point from air temperature and relative humidity, and see how comfortable the air will feel.
Advertisement
About the Dew Point Calculator
The dew point is the temperature to which air must cool for water vapor to condense into dew or fog. It is a better measure of how humid the air feels than relative humidity. This calculator uses the Magnus formula to convert air temperature and relative humidity into the dew point in Fahrenheit and Celsius.
How to use it
- Enter the air temperature and choose Fahrenheit or Celsius.
- Enter the relative humidity as a percentage.
- Press Calculate dew point to see the dew point and the comfort level.
Dew point comfort scale (°F)
| Dew point | How it feels |
|---|---|
| Below 50 | Dry and comfortable |
| 50 to 55 | Comfortable |
| 55 to 60 | Slightly humid |
| 60 to 65 | Sticky |
| 65 to 70 | Muggy |
| 70 or higher | Oppressive |
Dew point formula
γ = ln(RH ÷ 100) + aT ÷ (b + T); dew point = bγ ÷ (a − γ), with a = 17.62 and b = 243.12 °C. Temperatures are in Celsius in the formula.
Frequently asked questions
What is the dew point?
The temperature at which air becomes saturated and water vapor condenses. A higher dew point means more moisture in the air.
Is dew point or humidity better for comfort?
Dew point. Relative humidity changes with temperature, while dew point tells you the absolute moisture in the air.
What is a comfortable dew point?
Most people feel comfortable below about 60 °F. Above 65 °F it feels muggy and above 70 °F it feels oppressive.
How do I calculate dew point from humidity?
Use the Magnus formula with the temperature and relative humidity. This calculator does that for you.
Can the dew point be higher than the temperature?
No. At 100% humidity they are equal.
Last reviewed: November 2026.