Dew point chart
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Dew point
— °FAdd your readings for an estimate.
No location lookup or live weather.
Not medical advice. No result is a safety clearance. Follow official local and workplace guidance.
Your calculation record
Not medical advice.
Calculated reference matrix
Rows: air temperature in your chosen unit. Columns: relative humidity (%). Select a cell for a single answer above. Scroll horizontally inside the table on narrow screens, or use the row-by-row text alternative below. A dash means the combination is outside this site's supported output range.
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Row-by-row text alternative (no horizontal scrolling)
Not medical advice. Estimates only; follow official local and workplace guidance.
Not medical advice
This chart helps you compare the moisture in warm air. Each cell shows the estimated dew point for the air temperature at the left and the relative humidity at the top.
Unlike a heat-index table, it does not show an apparent temperature or a heat-illness risk level. A dew point of 20°C is not the same thing as air that feels like 20°C.
Reference values in Celsius
Values use the liquid-water Magnus-type approximation documented on our dew-point calculator. They are rounded to one decimal place.
| Air temperature | 30% RH | 50% RH | 70% RH | 90% RH |
|---|---|---|---|---|
| 20°C | 1.9°C | 9.3°C | 14.4°C | 18.3°C |
| 25°C | 6.2°C | 13.9°C | 19.1°C | 23.2°C |
| 30°C | 10.5°C | 18.4°C | 23.9°C | 28.2°C |
At the same temperature, higher relative humidity means a higher dew point. At the same relative humidity, warmer air also has a higher dew point. This is why comparing humidity percentages without temperatures can be confusing.
Read the gap between air temperature and dew point
A small gap means the air is close to saturation. At 100% relative humidity, the dew point equals the air temperature. A larger gap indicates more cooling would be needed to reach saturation without changing the air's moisture content.
The table does not predict exactly when a window will mist up or whether a room has a damp problem. Surface temperature, ventilation and changing moisture sources also matter.
Use the right reference for the job
These are calculated warm-air examples, not instrument observations. The method is based on NWS saturation-vapor-pressure documentation. It does not supply a frost-point calculation over ice or a full engineering psychrometric chart.
Use the calculator for intermediate values, and use the heat-index tool when your question is about apparent heat rather than condensation or moisture.
Method and transparency
Last updated: 6 November 2026. Not medical advice.