Dew point · liquid-water approximation
Dew point · liquid-water approximation: use air temperature, relative humidity. Review the formula, worked example and calculation steps.
Inputs
Use the units shown—
Enter your values and select Calculate.
Formula & explanation
γ = ln(RH/100)+17.67T/(243.5+T); Td = 243.5γ/(17.67−γ)
Variables & units
- Air temperature
- °C · minimum -40, maximum 50
- Relative humidity
- % · minimum 1, maximum 100
Worked example
25°C and 60% RH gives a dew point of approximately 16.705357°C.
Assumptions
Approximation using saturation over liquid water, restricted to −40 to 50°C and RH 1–100%. Below freezing, this is not the frost point.
References
Formula version 1.0.0. JavaScript floating-point arithmetic applies. Results display up to 6 decimal places; stored values retain available precision. Use the units shown.
Practice with an example
Use the default input values to find the answer. The reset icon restores those values.
Calculated on your device. Your latest 100 calculations stay in this browser.