Dew Point Calculator
Calculate the dew point temperature based on air temperature and relative humidity. Dew point is the best indicator of how humid and comfortable the air feels.
Slightly muggy. Some people begin to feel the humidity at this level.
Dew Point Comfort Levels
Very comfortable. Air feels dry and pleasant for all activities.
Pleasant conditions. Most people find this ideal.
Slightly muggy. Some sensitivity to humidity begins.
Uncomfortable for most. You'll notice the humidity.
Oppressive. Sweating becomes less effective for cooling.
Dangerous. High risk of heat-related illness.
Understanding Dew Point
What is Dew Point?
The dew point is the temperature at which air becomes saturated with water vapor and dew begins to form. It's an absolute measure of moisture in the air, unlike relative humidity which changes with temperature.
Why Dew Point Matters
Dew point is the best indicator of comfort because it directly measures how much moisture is in the air. High dew points make it harder for sweat to evaporate, making you feel hotter and more uncomfortable.
Dew Point vs. Humidity
Relative humidity can be misleading: 50% humidity at 90°F feels much worse than 50% at 60°F. Dew point gives a consistent measure: a 70°F dew point always feels oppressive, regardless of the actual temperature.
How is Dew Point Calculated?
This calculator uses the Magnus-Tetens approximation, a widely used formula that provides accurate dew point calculations for temperatures between -40°C and 50°C. The formula relates temperature, humidity, and the saturation vapor pressure of water.
Note: Dew point can never exceed the current air temperature. When the dew point equals the air temperature, relative humidity is 100% and fog or dew is likely to form.
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