Dew Point Calculator
Dew point from temperature and humidity.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Dew point
- 18.19 °C
- In Fahrenheit
- 64.74 °F
- Comfort level
- Humid
- Spread from air temp
- 5.81 °C
- Fog likely if temp falls to
- 18.2 °C
Working
- 1α = ln(70/100) + (17.625 × 24)/(243.04 + 24) = 1.2274
Quick answer
Dew point is the temperature at which air becomes saturated; above 20°C (68°F) most people find the air oppressive.
Td = (b·α) ÷ (a − α), α = ln(RH/100) + aT/(b+T)
How to use the Dew Point Calculator
- 1Enter the air temperature in Celsius.
- 2Enter relative humidity.
- 3Read the dew point and comfort level.
Frequently asked questions
Why is dew point better than humidity?
Relative humidity depends on temperature; dew point is an absolute measure of moisture, so 20°C dew point feels muggy anywhere.
When does condensation form?
When a surface is at or below the dew point — that's why cold glasses sweat and windows fog.