Dew Point Calculator
Estimate the dew point temperature from any air temperature and relative humidity pair, then explore each calculation step.
Input values
All fields use Celsius degrees and percentage units.
Dew point is the temperature where air becomes saturated; lower humidity yields a lower dew point.
How to Use This Calculator
Enter the air temperature in Celsius and the relative humidity between 0 and 100%. Then click "Calculate" or rely on the automatic update after editing inputs.
The output shows the dew point temperature as a monthly equivalent in the result banner, with supporting KPIs describing the inputs and intermediate alpha value.
Methodology
The Magnus-Tetens approximation is used to derive the dew point from temperature and humidity. It computes a helper variable alpha that tracks the logarithmic relationship between vapor pressure and temperature, then isolates the dew point.
Full original guide (expanded)
Data Source and Context
All calculations are based on the Magnus-Tetens approximation, commonly used in meteorology to estimate the saturation vapor pressure of water in air. Learn more about the Magnus formula.
Glossary of Terms
- Temperature (T): The air temperature in degrees Celsius.
- Relative Humidity (RH): The moisture level expressed as a percentage of the maximum at that temperature.
- Dew Point (Td): The temperature at which saturation and condensation begin.
Example Calculation
For a temperature of 25°C and 50% relative humidity, the Magnus-Tetens formula estimates a dew point of about 13.90°C.
Frequently Asked Questions (FAQ)
What is dew point?
The dew point is the temperature at which air becomes saturated with moisture and dew can form.
Why is dew point important?
Dew point helps evaluate humidity's impact on comfort, engineering, and weather prediction.
How accurate is this calculator?
This tool uses the Magnus-Tetens approximation, which is widely accepted in scientific and meteorological contexts for its accuracy.