Enter your air temperature and relative humidity to calculate the dew point temperature. Choose your preferred unit (Fahrenheit, Celsius, or Kelvin) and get back the dew point, absolute humidity, and a breakdown of atmospheric moisture conditions.
Dew Point Temperature
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Dew Point (°F)
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Dew Point (K)
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Absolute Humidity
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Frost Point
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Comfort Level
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The dew point is the temperature to which air must be cooled (at constant pressure and humidity) for water vapor to condense into liquid water (dew). When the actual air temperature drops to the dew point, the relative humidity reaches 100% and condensation begins to form on surfaces.
Humidity refers to the amount of water vapor present in the air. Relative humidity (RH) expresses this as a percentage of the maximum water vapor the air can hold at a given temperature. Absolute humidity is the actual mass of water vapor per unit volume of air, typically expressed in grams per cubic meter (g/m³).
Dew point is calculated using the Magnus formula. Given the air temperature (T in °C) and relative humidity (RH), the dew point Td ≈ (243.04 × [ln(RH/100) + (17.625×T)/(243.04+T)]) / (17.625 − [ln(RH/100) + (17.625×T)/(243.04+T)]). This approximation is accurate across typical atmospheric temperature ranges.
Relative humidity tells you how close the air is to saturation as a percentage, and it changes with temperature. The dew point is an absolute measure of atmospheric moisture — it stays constant as long as the amount of water vapor in the air doesn't change. A higher dew point means there is more moisture in the air.
Dew points below 10°C (50°F) feel dry and comfortable. Values between 13–16°C (55–61°F) feel pleasant. Once the dew point rises above 18°C (65°F), most people begin to feel humid and sticky. Dew points above 21°C (70°F) are considered oppressive and can be dangerous for people doing strenuous activities outdoors.
The frost point is similar to the dew point, but it refers to the temperature at which water vapor deposits directly as frost (ice) rather than liquid dew. It is slightly lower than the dew point and is most relevant when temperatures are already near or below freezing (0°C / 32°F).
No. The dew point can never exceed the actual air temperature. When they are equal, the relative humidity is 100% and the air is fully saturated — conditions that produce fog, mist, or precipitation. A very small difference between air temperature and dew point is a sign of high humidity.
Absolute humidity is the total mass of water vapor contained in a given volume of air, expressed in grams per cubic meter (g/m³). Unlike relative humidity, it does not depend on temperature and directly represents the actual water content of the air. Relative humidity, on the other hand, compares current vapor content to the maximum possible at that temperature.