justyourcalculatorDew Point Calculator
Dew point from temperature and humidity, or humidity from the dew point.
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Dew Point Calculator
Dew point or relative humidity from the other
Dew point
62.1 °F
Getting sticky
- In the other unit
- 16.7 °C
- Temperature minus dew pointFog and dew form as this nears zero
- 14.9 °F
Magnus formula with Alduchov-Eskridge constants (b = 17.625, c = 243.04 °C), accurate to about 0.4 °C between -40 and 50 °C.
How it was calculated
- γ = ln(RH/100) + 17.625 × T ÷ (243.04 + T) = 1.13305
- Td = 243.04 × γ ÷ (17.625 - γ) = 16.7 °C
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How the dew point calculator works
The dew point is the temperature air must cool to (at constant pressure and moisture) for water vapor to condense into dew. Unlike relative humidity, it measures how much moisture is actually in the air, which is why it is the better guide to how muggy it feels.
This calculator uses the Magnus approximation: γ = ln(RH/100) + bT/(c + T) and Td = cγ/(b - γ), with b = 17.625 and c = 243.04 °C. Reversing it gives relative humidity from the temperature and dew point.
Using and checking your result
Published by JustYourCalculator. Check the units and assumptions above, and compare a known example before relying on the output. Calculations use browser arithmetic and may round displayed values.
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