Humidity feels worse when the dew point is high, even if the thermometer reading stays the same.
About this calculator
Humidity feels worse when the dew point is high, even if the thermometer reading stays the same. This calculator takes air temperature in Celsius and relative humidity percent, then returns the dew point and a short comfort label.
Dew point marks the temperature where water vapour condenses. A dew point above 21°C feels like Mumbai monsoon air — sweat does not evaporate quickly. Below 10°C the air feels dry. HVAC engineers use dew point to size dehumidifiers; athletes use it to decide whether outdoor training is safe.
Example: 32°C at 70% RH gives a dew point near 25°C — oppressive for manual labour. Drop humidity to 40% at the same temperature and dew point falls to about 17°C, which most people find tolerable.
Compare with the [[heat-index]] calculator for felt temperature in sun and wind, the [[wind-chill]] calculator for cold exposure, and the [[btu]] calculator when sizing cooling load for a room.
Common uses
- Checking outdoor comfort before cricket practice or a construction shift
- HVAC and dehumidifier sizing for coastal flats in Chennai or Kochi
- Greenhouse and storage humidity control
- Explaining why 30°C in Delhi dry season feels different from 30°C in Kolkata
- Weather briefings when relative humidity is reported but dew point is not
Frequently asked questions
What dew point is comfortable for outdoor work?
Below 16°C feels comfortable for most people. Between 18°C and 21°C feels sticky and raises sweat risk. Above 21°C is oppressive — schedule heavy work for early morning or provide shade and water.
How is dew point different from relative humidity?
Relative humidity depends on both moisture and temperature — it drops when air heats up even if moisture stays the same. Dew point is one number for moisture content, so 20°C dew point feels similarly humid whether the air is 25°C or 35°C.
What is the dew point at 30°C and 80% humidity?
Enter temperature 30 and humidity 80. The dew point comes out near 26°C — very humid. The comfort label will warn about oppressive conditions similar to peak monsoon afternoons on the west coast.
Which formula does this calculator use?
It uses the Magnus approximation with constants a = 17.27 and b = 237.7 for Celsius inputs. This is standard for weather apps and engineering estimates between about −40°C and 60°C.
Can dew point be higher than air temperature?
Under normal conditions dew point equals or stays below the current air temperature. If you see fog or condensation, air temperature is at or below the dew point. Enter valid RH between 1% and 100% for a result.