💧 Dew Point Calculator
This calculator estimates the temperature to which air must be cooled to become saturated with water vapor and form dew
Result
Dew Point Temperature:
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Dew Point Calculator
The Dew Point Calculator helps you accurately determine the temperature at which air becomes fully saturated with water vapor, causing dew formation. Simply enter any two values — air temperature, relative humidity, or dew point — and the calculator will compute the third parameter instantly.
What Is Humidity?
Humidity is the measure of the amount of water vapor present in the air. It plays a major role in weather conditions such as dew, frost, fog, and rainfall.
When the air contains a large amount of water vapor, it feels damp or sticky — this is called high humidity. On the other hand, dry air with very little moisture represents low humidity.
The ability of air to hold water vapor depends on temperature — warm air can hold more moisture than cool air before reaching its saturation point.
There are two primary types of humidity measurements:
1. Absolute Humidity
Absolute humidity is the actual quantity of water vapor present in a given volume of air, usually expressed in grams per cubic meter (g/m³).
It represents the total water content, regardless of temperature changes. However, in the open atmosphere, temperature and pressure variations can cause absolute humidity to fluctuate.
2. Relative Humidity
Relative humidity (RH) compares the current amount of moisture in the air to the maximum amount the air can hold at a given temperature.
It is expressed as a percentage (%).
A relative humidity of 100% means the air is completely saturated — no more water vapor can be absorbed, and dew will start to form.
Lower RH levels indicate drier air.
In weather forecasts, relative humidity is a common term because it influences comfort level, perceived temperature (heat index), and precipitation potential.
For example:
High humidity makes hot weather feel even hotter because sweat cannot evaporate efficiently.
Low humidity, on the other hand, can cause dry skin, throat irritation, and static electricity.
What Is Dew Point?
The dew point is the temperature at which air must be cooled (at constant pressure) for it to become saturated with water vapor. When this temperature is reached, condensation begins — forming dew on surfaces like grass, leaves, or windows.
Key Facts About Dew Point:
When dew point equals air temperature, the relative humidity is 100%.
A higher dew point indicates more moisture in the air and a more humid environment.
A lower dew point signifies dry air and a more comfortable atmosphere.
For instance:
A dew point above 20°C (68°F) feels muggy or uncomfortable.
A dew point below 10°C (50°F) feels dry and crisp.
If the dew point is below 0°C (32°F), frost forms instead of dew because water vapor freezes directly.
In aviation and meteorology, dew point is used to predict fog, frost, and even aircraft carburetor icing.
Devices like dew point meters measure it directly by cooling a metal surface until condensation appears.
Why Dew Point Matters:
Understanding the dew point helps in many real-world situations:
Weather Forecasting: Predicting fog, rainfall, and visibility.
Comfort Level: High dew points make hot days feel sticky and uncomfortable.
HVAC & Indoor Air Quality: Maintaining the right dew point prevents mold growth and keeps air comfortable.
Industrial Applications: Controlling moisture levels in sensitive manufacturing processes.
The U.S. Occupational Safety and Health Administration (OSHA) recommends maintaining indoor temperatures between 68–76°F (20–24°C) with relative humidity between 20–60% for comfort and health.
How the Dew Point Calculator Works:
This online dew point calculator uses the scientifically accepted Magnus formula to estimate the dew point temperature from air temperature and relative humidity.
Input Options:
You can enter:
Air Temperature (in °C, °F, or K)
Relative Humidity (%)
Dew Point Temperature (in °C, °F, or K)
Provide any two values, and the calculator will compute the third.
Output Details:
Along with the calculated value, this tool also provides:
Water Vapor Pressure (Pa)
Saturation Vapor Pressure (Pa)
Absolute Humidity (g/m³)
Moisture Volume Concentration (ppm)
Moisture Weight Concentration (ppm)
This makes it useful not only for meteorological purposes but also for industrial, HVAC, and scientific applications.
Final Thoughts:
The dew point is a powerful indicator of air moisture and comfort level.
By understanding how temperature and humidity interact, you can better interpret weather reports, improve indoor comfort, and monitor environmental conditions.
Use our Dew Point Calculator to get precise, science-backed results instantly — and stay informed about the world of humidity and atmospheric conditions.
Related Calculators:
The Dew Point shows the actual amount of moisture in the air — it’s the temperature at which air becomes saturated. It tells you how “muggy” it feels. Relative Humidity (RH), on the other hand, is a percentage showing how full of moisture the air is compared to its maximum capacity at that temperature. RH changes with temperature, but the Dew Point stays the same.
For a comfortable and healthy indoor environment, the ideal dew point is between 50°F and 60°F (10°C to 16°C), with indoor temperatures between 68°F and 76°F. Dew points above 65°F (18°C) usually feel humid and uncomfortable.
No, the dew point can never be higher than the air temperature. If it were, the air would already be oversaturated — which doesn’t happen in normal conditions.
It means the air is fully saturated with moisture and can’t hold any more. At this point, the air temperature equals the dew point, and condensation, fog, or dew starts to form.
High dew points mean there’s more moisture in the air, which slows down sweat evaporation — your body’s cooling process. As a result, you feel much hotter than the actual temperature.
Absolute Humidity measures the actual amount of water vapor in the air (grams per cubic meter). Relative Humidity is a percentage comparing that amount to the air’s moisture capacity at a given temperature.
When the dew point falls below 32°F (0°C), water vapor skips the liquid phase and turns directly into ice crystals — a process called deposition — forming frost instead of dew.