Dew Point Calculator: When Will Dew Form?
Dew forms when surfaces cool to the dew point. This calculator finds that temperature from air temperature and humidity.
What is the Dew Point Calculator?
The dew point is the temperature at which air becomes saturated and dew forms. Enter temperature in Celsius and relative humidity and this tool calculates it with the Magnus formula, which is useful for judging condensation and muggy air.
How to use it
- Enter your values in the fields provided.
- Click Calculate Dew Point.
- Read the result and adjust an input if you want a different outcome.
Worked example
At 25 C and 60 percent humidity, the dew point is about 16.68 C.
What is the dew point at 25 C and 60 percent humidity?
The Magnus formula gives about 16.68 C, so surfaces cooling below that temperature will collect dew.
Frequently asked questions
What do I enter to get a result?
Fill in every field with your own numbers or choices, then run the tool. Empty number fields count as zero, so check them before you trust the output.
Can I reuse this result elsewhere?
Yes. The result is calculated in your browser from the values you entered, so you can copy the numbers into your own notes or plan.