Dew Point Calculator
Enter temperature and humidity. Get exact dew point and human-comfort description. Uses the Magnus formula, accurate to within 0.5°C.
Dew Point Comfort Chart
| Dew Point | How it feels | Severe weather relevance |
|---|---|---|
| < 50°F | Dry, comfortable | Low tornado risk |
| 50-55°F | Comfortable | Marginal moisture |
| 55-60°F | Comfortable | Enough moisture for storms |
| 60-65°F | Slightly humid | Supercells possible |
| 65-70°F | Humid, sticky | Tornado favored |
| 70-75°F | Very humid, oppressive | Tornado risk high with shear |
| 75°F+ | Miserable | Rare in Plains; common Deep South |
Why dew point matters for severe weather
Dew point measures actual moisture content in the air — unlike relative humidity, which changes with temperature. A dew point of 68°F contains a lot of moisture whether the air is 75° or 95°.
For a supercell tornado, forecasters look for dew points in the 60s Fahrenheit. Below 55°F, the air is usually too dry to sustain the strong low-level circulation that produces tornadoes. Above 70°F, moisture is plentiful but instability often becomes explosive.
The Magnus formula used here: γ = ln(RH/100) + a·T/(b+T); Td = b·γ/(a-γ), where a = 17.625, b = 243.04°C.
Related: Thunder Distance · Wind Speed Converter · Reading a Skew-T