Dew Point Calculator
Dew point, humidity and condensation
Temperature & Humidity
Dew point
62.0°F
Dew point-
Relative humidity-
Absolute humidity-
Temperature − dew point-
Dew Point Chart (°F)
| Temp \ RH | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|
| 40°F | 11 | 18 | 23 | 27 | 31 | 34 | 37 |
| 50°F | 20 | 27 | 32 | 37 | 41 | 44 | 47 |
| 60°F | 28 | 36 | 41 | 46 | 50 | 54 | 57 |
| 70°F | 37 | 45 | 50 | 55 | 60 | 64 | 67 |
| 80°F | 46 | 54 | 60 | 65 | 69 | 73 | 77 |
| 90°F | 54 | 62 | 69 | 74 | 79 | 83 | 87 |
| 100°F | 63 | 71 | 78 | 84 | 88 | 93 | 97 |
Dew Point Comfort Scale
| Dew point | How it feels |
|---|---|
| Below 55°F | Dry, comfortable |
| 55–60°F | Comfortable |
| 60–65°F | A bit sticky |
| 65–70°F | Humid, uncomfortable |
| 70–75°F | Very humid, oppressive |
| 75°F and above | Extremely humid |
Relative humidity changes with temperature, but dew point measures the actual moisture, so it's the better guide to how muggy it feels. When the air cools toward the dew point, camera lenses fog — astrophotographers use dew heaters.
Formulas & Sources
- Magnus formula: γ = ln(RH/100) + bT/(c+T), dew point = cγ/(b−γ), b = 17.62, c = 243.12 °C (WMO)
- Absolute humidity = 216.7 × vapor pressure (hPa) ÷ (T + 273.15) · comfort scale after the US National Weather Service
Last reviewed: 2026-10-19
FAQ
What is the dew point?
The temperature at which air becomes saturated and water starts to condense. At 77°F and 60% humidity the dew point is about 62°F.
Why is dew point better than relative humidity?
Relative humidity drops as the air warms even if moisture stays the same. Dew point measures the moisture itself, so it tracks how muggy it feels.
What dew point feels uncomfortable?
Above about 60°F it starts to feel sticky; above 70°F it feels oppressive.
Why do windows get condensation?
When a window's surface is colder than the indoor dew point, moisture condenses on it. At 68°F and 60% humidity indoors, that's about 54°F.
How do I stop my camera lens from fogging?
Keep the lens above the dew point — use a dew heater for night shoots and let gear warm up slowly in a closed bag.