Dew Point Calculator: Convert Humidity to Dew Point and Back
Measure the moisture threshold directly: Calculate the dew point from temperature and relative humidity, or work backwards from dew point to humidity, with comfort level and cloud base.
Dew point
65°F (18°C)
How it feels
Slightly sticky
Estimated cloud base
3,400 ft (1,050 m)
◇
How close the air is to condensation
Temperature spread14°F
Fog or dew signalNot close to saturation
The smaller the temperature-to-dew-point spread, the closer the air is to fog, dew or a low cloud base.
From dew point to condensation and cloud base
The dew point is the temperature at which air becomes saturated and water starts to condense. It works in both directions here: enter temperature and relative humidity to get the dew point, or temperature and dew point to get the relative humidity. It also estimates the height of the cloud base for rising air.
For the evidence, limits and practical use behind this result, read Dew Point vs. Humidity. The weather tools guide explains when each calculator is the right one.
Magnus formula (Alduchov and Eskridge constants)Td = 243.04·γ / (17.625 − γ)Cloud base ≈ 125 m per °C of spread
Interpret the temperature-to-dew-point spread
- A dew point above 65°F (18°C) feels muggy whatever the relative humidity says.
- A small spread means fog or dew. When temperature and dew point are within 2-3°F (1-2°C), expect condensation on cars and grass.
- The cloud base estimate is for convective clouds. It works best for fair-weather cumulus on a sunny afternoon.
How dew point feels
| Dew point | How it feels |
|---|---|
| Below 50°F (10°C) | Dry and comfortable |
| 50-60°F (10-16°C) | Pleasant |
| 60-65°F (16-18°C) | Slightly sticky |
| 65-70°F (18-21°C) | Muggy |
| 70-75°F (21-24°C) | Oppressive |
| Above 75°F (24°C) | Miserable |
Dew, fog, comfort and cloud questions
Can the dew point be higher than the temperature?
No. The dew point can equal the air temperature, which means 100% relative humidity and saturated air, but it cannot exceed it for long.
What is a comfortable dew point indoors?
Roughly 40-55°F (4-13°C). Below that the air feels dry and static builds up; above 60°F (16°C) indoor air starts to feel clammy.
How is the cloud base estimated?
Rising air cools faster than its dew point drops, and the two meet about 125 m (410 ft) higher for every 1°C of spread between temperature and dew point at the ground. It is an estimate for convective clouds, not for layered cloud.