What Is the Dew Point & Psychrometric Humidity Calculator?
Dew point is the temperature to which air must be cooled at constant barometric pressure for water vapor to condense into liquid dew or fog.
Unlike relative humidity (which changes with temperature), dew point provides an absolute indicator of atmospheric moisture content.
How Does the Dew Point & Psychrometric Humidity Calculator Work?
Converts dry-bulb temperature into Celsius.
Computes the Magnus psychrometric parameter γ incorporating the natural logarithm of fractional humidity.
Calculates dew point temperature and converts to Fahrenheit.
Dew Point & Psychrometric Humidity Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
The Magnus-Tetens approximation relates dry-bulb temperature and relative humidity to vapor pressure saturation.
How to Use the Dew Point & Psychrometric Humidity Calculator
- Enter ambient air temperature.
- Enter relative humidity percentage.
- Read dew point temperature and human comfort interpretation.
Step-by-Step Example Calculation
78°F Air Temp with 65% Relative Humidity
Input Values:
Understanding Your Result
Identifies the exact surface temperature that will cause sweating on cold pipes, glass windows, or refrigerated cases.
Factors That Affect the Result
- Barometric altitude pressure (minor effect compared to vapor content).
When Should You Use This Calculator?
- Setting dehumidifier thresholds, coating and painting surface prep, and weather forecasting.
Assumptions & Limitations
- Standard sea-level barometric pressure (1013.25 hPa).
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard Magnus-Tetens psychrometric formulation.