Dew Point Calculator
Calculate dew point and atmospheric moisture properties from temperature and relative humidity.
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Advanced: Atmospheric Pressure
Pa
Optional. Default = 101,325 Pa. Local weather automatically updates this value when available.
Dew Point
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Water Vapor Pressure
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Saturation Water Vapor Pressure
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Absolute Humidity
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Moisture Volume Concentration
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Moisture Weight Concentration
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Temperature–Dew Point Difference
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Atmospheric Pressure Used
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Dew point: The temperature at which air becomes saturated with water vapour and condensation can begin.
Water Vapor Pressure =
RH × Saturation Vapor Pressure / 100
Absolute Humidity = Vapor Pressure / (Rᵥ × Temperature)
ppmv = Vapor Pressure / Atmospheric Pressure × 10⁶
Absolute Humidity = Vapor Pressure / (Rᵥ × Temperature)
ppmv = Vapor Pressure / Atmospheric Pressure × 10⁶
Saturation water vapor pressure is calculated using the Buck equation. Atmospheric pressure affects the ppmv and ppmw moisture concentrations, but is not required to determine the basic dew point.
Standard atmospheric pressure of 101,325 Pa is used by default. Expand the advanced section to enter another pressure, or use local weather to obtain surface pressure automatically.