Dew Point Calculator

Dew Point
60.4°F

What Is a Dew Point Calculator?

Dew point is the temperature at which air becomes saturated with moisture and water vapor begins to condense. Unlike relative humidity (which depends on air temperature), dew point directly indicates how much moisture is actually in the air — making it a more consistent measure of how "muggy" conditions will feel.

How to Use the Dew Point Calculator

  1. Enter the current air temperature.
  2. Enter the relative humidity.
  3. View the calculated dew point and comfort level.

Dew Point Formula (Magnus Approximation)

Dew Point (Celsius)
Td = (b×α) / (a−α), where α = ln(RH/100) + (a×T)/(b+T)
a = 17.27
b = 237.7
T = temperature in °C
RH = relative humidity %

Comfort Level Reference

Dew Point (°F)Comfort Level
Below 55Dry, comfortable
55–60Comfortable
60–65Slightly humid
65–70Humid, muggy
Above 70Very muggy, oppressive

Why Dew Point Is More Useful Than Relative Humidity Alone

Relative humidity is relative to the current temperature — 60% humidity feels very different at 60°F versus 90°F. Dew point remains a more consistent, direct measure of actual moisture content in the air, which is why meteorologists often prefer it for describing how muggy conditions feel.

Frequently Asked Questions

The temperature at which air becomes fully saturated with water vapor and condensation begins to form — a direct measure of the actual moisture content in the air.

Because relative humidity changes with temperature even if actual moisture stays constant, while dew point directly reflects the amount of moisture present, making it more consistent for describing how muggy conditions feel.

Generally, dew points below 60°F are considered comfortable, while dew points above 65-70°F are often described as muggy or oppressive.

No — dew point can never exceed air temperature, since air must cool to reach saturation, and dew point represents that saturation temperature.

It indicates the air is close to saturation (high relative humidity), often associated with fog, dew formation, or muggy conditions.