Humidity Calculator
Enter the temperature and one of relative humidity or dew point. The calculator fills in the rest — dew point or relative humidity, absolute humidity, vapor pressure, and how the air actually feels.
| Dew point | — |
|---|---|
| Relative humidity | — |
| Absolute humidity | — |
| Vapor pressure | — |
The three ways to describe moisture
Relative humidity is the percentage of moisture the air holds compared with the most it could hold at that temperature. It is the number you hear most, but it is misleading, because warm air can hold far more water than cold air. Fifty percent on a hot day is much muggier than fifty percent on a cold one.
Dew point is the temperature the air must cool to before moisture condenses. Unlike relative humidity, it barely changes as the day warms and cools, so meteorologists trust it as the honest measure of how humid it really feels. A dew point above 65°F feels sticky; above 70°F feels oppressive.
Absolute humidity is the actual mass of water vapour in a cubic metre of air, in grams. It is what matters for things like drying, condensation, and how much water the atmosphere is genuinely carrying.
Dew point comfort guide
| Dew point | How it feels |
|---|---|
| Below 50°F | Dry, crisp, very comfortable |
| 50–60°F | Comfortable for most people |
| 60–65°F | Noticeably humid, getting sticky |
| 65–70°F | Humid and uncomfortable |
| 70–75°F | Oppressive, sweat does not evaporate well |
| Above 75°F | Miserable and potentially dangerous |
Why this matters for storms
High dew points are fuel for severe weather. When Gulf moisture with dew points in the 70s streams north into the Plains, it loads the atmosphere with the energy that powers supercells and tornadoes. Forecasters watch the dew point line as closely as the temperature.