Dew Point Calculator
Calculate the dew point temperature based on air temperature and relative humidity.
About Dew Point
The dew point is the temperature at which air becomes saturated with water vapor, causing condensation to occur. It's an important meteorological measurement that helps in understanding weather conditions and predicting fog, dew, and frost formation.
What is Dew Point?
Dew point is the temperature to which air must be cooled to become saturated with water vapor. When the dew point temperature is reached, water vapor condenses into liquid water, forming dew on surfaces. The higher the dew point, the more moisture is in the air.
Relationship to Humidity
Dew point is directly related to relative humidity:
- When relative humidity is 100%, the dew point equals the air temperature
- The closer the dew point is to the air temperature, the higher the relative humidity
- A large difference between dew point and air temperature indicates low humidity
Comfort Scale
How dew point affects human comfort:
- Below 10°C (50°F): Very comfortable
- 10-12°C (50-54°F): Comfortable
- 13-15°C (55-59°F): Moderately comfortable
- 16-17°C (60-64°F): Slightly uncomfortable
- 18-20°C (65-69°F): Uncomfortable, humid
- 21-23°C (70-74°F): Very uncomfortable, very humid
- Above 24°C (75°F): Extremely uncomfortable, oppressive
Practical Applications
- Weather Forecasting: Helps predict fog, dew, and frost formation
- Aviation: Critical for assessing visibility conditions and aircraft performance
- Agriculture: Important for crop management and frost protection
- Building Management: Useful for controlling indoor humidity and preventing condensation
- Personal Comfort: Helps understand how weather will feel regardless of temperature
Dew Point vs. Frost Point
When the dew point is below freezing (0°C or 32°F), it's called the frost point. At this point, water vapor transitions directly from gas to solid, forming frost instead of dew.
How to Use This Calculator
- Enter the current air temperature in the first field.
- Select the temperature unit (Celsius or Fahrenheit).
- Enter the relative humidity percentage (0-100%) in the second field.
- Click "Calculate Dew Point" to see the results.
Pro Tips:
- For weather forecasting, monitor the dew point trend over time.
- When the dew point approaches the air temperature, expect fog or precipitation.
- For indoor comfort, aim to keep the dew point below 16°C (60°F).
- Higher dew points (above 18°C or 65°F) will feel increasingly muggy and uncomfortable.
Note:
This calculator uses the Magnus-Tetens formula, which is highly accurate for temperatures between -45°C and 60°C (-49°F and 140°F).