Dew Point Calculator
Calculate the dew point from air temperature and relative humidity — key to predicting frost and dew.
Dew point is the temperature at which air becomes saturated and moisture condenses (Magnus formula). When the dew point is at or below 0°C and a clear, calm night lets temperature fall to it, frost forms. A dew point well above 0°C means frost is unlikely even on a cold night.
Indicative planning figures based on published research averages. Local soil tests, varieties and weather change actual requirements — confirm with your agronomist or extension officer.
Orchardists and growers use the free Dew Point Calculator for an accurate answer in seconds — no formulas to remember, works offline in the orchard.
About Dew Point Calculator
Dew point is one of the most useful numbers in frost forecasting: it's the temperature at which the air's moisture would condense, and on a clear, calm night the air temperature falls toward it. If the dew point is at or below freezing, frost becomes likely once temperature reaches it; if it's well above zero, frost is improbable even on a chilly night. This tool computes dew point from temperature and humidity using the standard Magnus formula, so you can anticipate frost (and dew/disease) risk.
How to use Dew Point Calculator
- 1Enter your values into the inputs.
- 2Read the headline result and the supporting breakdown.
- 3Apply the guidance in the note to your orchard decisions.
Why use Dew Point Calculator?
- ✓Uses the standard, citable formula
- ✓Clear inputs with sensible defaults
- ✓Instant result with the working shown
- ✓Free, fully in-browser and private
Frequently asked questions
How does dew point predict frost?+
On a clear, still night, air temperature drops toward the dew point. If the dew point is at or below 0°C, frost can form when temperature reaches it; the latent heat released as dew/frost forms also slows further cooling. A dew point well above 0°C makes damaging frost unlikely.
What is dew point?+
The temperature to which air must cool, at constant pressure, to become saturated so water condenses. It depends on temperature and humidity — humid air has a dew point close to the air temperature; dry air has a much lower dew point.
Is this tool free and private?+
Yes — free, no sign-up, and all calculation runs in your browser, so it works offline in the orchard and your data never leaves the device.
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