Dew Point
58°F
Celsius
14°C
Comfort
Slightly Humid
Dew Point Temperature
58°F
14.3°C
Comfort
Slightly Humid
Spread
17°F
Inputs
Result
Convert to °C: 23.9. α = (17.27×23.9)/(237.7+23.9) + ln(0.55) = 0.979. Td = (237.7×0.979)/(17.27−0.979) = 14.3°C = 58°F.
Inputs
Result
Dew point 78°F is in the "oppressive" range. Outdoor activity should be limited.
Dew point is the temperature at which air becomes saturated and moisture condenses. It is a better comfort indicator than relative humidity because it directly measures moisture content. A dew point above 65°F feels humid; above 70°F feels oppressive.
| Dew Point | Comfort | Feels Like |
|---|---|---|
| <50°F | Pleasant | Dry air, easy breathing |
| 55–60°F | Comfortable | Slightly muggy |
| 65–70°F | Humid | Sweating, sticky |
| >70°F | Oppressive | Tropical, exhausting |
The Magnus formula calculates dew point from temperature and humidity: α = (a×T)/(b+T) + ln(RH/100), then Td = (b×α)/(a−α), where a=17.27, b=237.7°C. This gives accuracy within ±0.4°C for most conditions.
The spread is the difference between air temperature and dew point. A small spread (under 5°F) means fog is likely. Pilots use the spread to estimate cloud base height: divide spread by 4.4 and multiply by 1,000 for altitude in feet.
Yes. Relative humidity varies with temperature (hot air holds more moisture), so 50% humidity at 90°F is much more humid than 50% at 70°F. Dew point gives the absolute moisture level regardless of temperature.
Weather and outdoor calculators
Last Updated: Mar 20, 2026
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