Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Dew point
69.1
Dew point (°C)
20.6
Comfort level
Humid
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter air temperature (°F).
- 2Enter relative humidity (%).
- 3Read your dew point on the right — it updates as you type.
- 4Hit Share to keep the scenario or send it to someone.
About this calculator
Dew point is the temperature air must cool to for water vapor to condense, and unlike relative humidity it directly tells you how muggy the air actually feels regardless of temperature. A 60°F dew point feels sticky whether the air temp is 75°F or 95°F, which is why meteorologists prefer it over RH for describing outdoor comfort. This calculator uses the Magnus-Tetens approximation, accurate to within about 0.4°C across typical weather ranges. Dew point also predicts fog and frost formation: when overnight lows approach the dew point, expect fog, and if the dew point is at or below freezing, expect frost instead of dew.
Worked example
Using the values the calculator loads with:
Inputs
- Air temperature: 82 °F
- Relative humidity: 65 %
Results
- Dew point: 69.1
- Dew point (°C): 20.6
- Comfort level: Humid
What each field means
Inputs
- Air temperature (°F)
- The air temperature used in the calculation, measured in °F. Starts at 82 °F so you have a working example on load. Accepted range: -20–130 °F.
- Relative humidity (%)
- The relative humidity used in the calculation, measured in %. Starts at 65 % so you have a working example on load. Accepted range: 1–100 %.
Results
- Dew point
- Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Dew point (°C)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Comfort level
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why is dew point a better muggy-day indicator than humidity percentage?
Relative humidity is relative to the current temperature, so 50% RH at 60°F holds far less actual moisture than 50% RH at 95°F. Dew point measures absolute moisture content directly, so a 68°F dew point feels equally sticky whether it's 80°F or 100°F outside.
What dew point predicts frost?
If the dew point is at or below 32°F and the surface cools to that temperature overnight, water vapor deposits directly as frost instead of condensing as dew, which is why forecasters watch dew point closely during shoulder-season nights.
Can dew point ever be higher than air temperature?
No — dew point can equal air temperature (100% RH, saturated air, typically producing fog or rain) but can never exceed it, since that would mean condensation happens above the actual air temperature, which is physically impossible.
What dew point is considered uncomfortable outdoors?
Most people start feeling sticky around 65°F, it's widely considered oppressive by 75°F, and dew points above 80°F (common in the Gulf Coast and Southeast Asia in summer) represent some of the most humid conditions found anywhere on Earth.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Dew Point Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/dew-point-calculator
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/dew-point-calculator" target="_blank" rel="noopener">Dew Point Calculator — RevenueLab</a> (2026).</p>
Source: [Dew Point Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/dew-point-calculator) (2026).