Dew Point vs. Relative Humidity: Which One Tells You How Muggy It Feels
Note: Some future links on this site may be affiliate links. We never claim hands-on testing; guides are researched from the public sources listed in each article.
How we wrote this: A plain-English summary of National Weather Service guidance (NWS La Crosse office explainer), checked October 29, 2026.
What dew point is
The dew point is the temperature air must be cooled to (at constant pressure) to reach 100% relative humidity. Cool the air further and water must come out as liquid, usually fog, dew or precipitation.
The higher the dew point, the more moisture is in the air, and the muggier it feels.
Why relative humidity can mislead
Relative humidity depends on temperature. The NWS's example:
- 30°F with a 30°F dew point gives 100% relative humidity.
- 80°F with a 60°F dew point gives 50% relative humidity.
The 80°F day feels much more humid, even though its RH is lower. To judge how dry or humid it will feel, look at the dew point.
Summer comfort guide (NWS)
| Dew point | How it feels |
|---|---|
| 55°F or lower | Dry and comfortable |
| 55–65°F | Becoming sticky, with muggy evenings |
| 65°F or higher | Lots of moisture; becoming oppressive |
Heat safety
Humidity makes heat more dangerous because sweat evaporates more slowly. The NWS heat index combines temperature and relative humidity; try our heat index calculator and see heat safety.
Related: what 40% chance of rain means, cloud types.