Dew Point Calculator
Calculate the dew point from temperature and relative humidity.
See comfort level and condensation risk.
Supports Fahrenheit and Celsius.
Dew Point & Comfort
Dew point is the temperature at which air becomes saturated and moisture condenses. It is calculated using the Magnus formula:
γ(T, RH) = ln(RH/100) + (b × T) / (c + T)
Dew Point = (c × γ) / (b − γ)
Where:
- T = temperature in °C
- RH = relative humidity (%)
- b = 17.67
- c = 243.5°C
Unit conversions:
- °F to °C:
(°F − 32) × 5/9 - °C to °F:
(°C × 9/5) + 32
Dew point comfort levels:
- Below 50°F (10°C): Dry — very comfortable
- 50–55°F (10–13°C): Comfortable
- 55–60°F (13–16°C): Noticeable — slightly humid
- 60–65°F (16–18°C): Sticky — uncomfortable for some
- 65–70°F (18–21°C): Oppressive — uncomfortable for most
- Above 70°F (21°C): Miserable — dangerous heat possible
Practical uses:
- HVAC system sizing
- Predicting fog or frost
- Preventing window condensation
- Protecting stored goods from moisture