Find the dew point from temperature and relative humidity, and see how humid it will actually feel.
Enter the air temperature and relative humidity, then click Calculate
This free dew point calculator uses the Magnus-Tetens approximation to convert air temperature and relative humidity into the dew point — the temperature at which air becomes fully saturated with moisture — along with a humidity comfort level rating that meteorologists consider more reliable than relative humidity alone.
Enter the current air temperature and relative humidity, and the calculator applies the Magnus-Tetens formula to solve for the dew point temperature. Unlike relative humidity, which is always relative to the current air temperature and therefore changes throughout the day even when the actual moisture content of the air stays constant, dew point measures the air's moisture content directly — a dew point of 65°F feels roughly the same whether the air temperature is 75°F or 95°F.
Anyone who wants a more accurate sense of how humid it will actually feel outside than relative humidity alone provides, pilots and outdoor enthusiasts checking fog or condensation risk, and gardeners or homeowners assessing mold and condensation risk indoors. It's a useful weather comfort tool for everyday planning.
The Magnus-Tetens approximation this calculator uses
This widely used formula approximates the physical relationship between temperature, humidity, and saturation vapor pressure, accurate to within about 0.4°C across typical Earth surface conditions.
Dew point represents the temperature at which the current amount of moisture in the air would saturate it completely — cooling air to that point causes condensation.
Because dew point reflects actual moisture content rather than a ratio to current temperature, it stays a consistent comfort indicator throughout a changing day.
From entering conditions to reading your result
Type the current air temperature in Fahrenheit or Celsius.
Type the current relative humidity as a percentage.
See the dew point temperature and its humidity comfort level rating.
A warm, moderately humid day and a hot, humid day
A commonly used chart for interpreting dew point comfort
| Dew Point (°F) | Dew Point (°C) | How It Feels |
|---|---|---|
| Below 50°F | Below 10°C | Dry — comfortable, low humidity |
| 50-55°F | 10-13°C | Very comfortable |
| 55-60°F | 13-16°C | Comfortable |
| 60-65°F | 16-18°C | OK for most, slightly humid at times |
| 65-70°F | 18-21°C | Somewhat uncomfortable, humid |
| 70-75°F | 21-24°C | Very humid, quite uncomfortable |
| Above 75°F | Above 24°C | Extremely uncomfortable, oppressive |
This scale is a widely used meteorological rule of thumb, not an exact physiological measurement — individual comfort varies, and factors like wind and sun exposure also affect how humid weather actually feels.
Where knowing the actual moisture content of the air matters
Check whether overnight temperatures are likely to drop to the dew point, signaling fog formation.
Assess indoor humidity comfort and condensation risk on windows or cold surfaces.
Pilots use dew point alongside temperature to assess visibility and icing risk.
Understand dew formation risk for crops, lawns, and outdoor plants.
Get a more reliable sense of how muggy conditions will feel than relative humidity alone provides.
What this dew point calculator does well, and where it has boundaries
Understand dew point correctly
Summary: This dew point calculator uses the Magnus-Tetens formula to turn temperature and relative humidity into the dew point and a humidity comfort rating — free, instant, and a more reliable comfort indicator than relative humidity alone. Pair it with the Heat Index Calculator or Wind Chill Calculator for other weather comfort calculations.
Common questions about dew point
Official weather agency references to complement this calculator
Other weather and measurement tools