Frost Point Calculator

Frost Point Calculator

Estimate the frost point - the sub-freezing counterpart to dew point - from a given below-freezing dew point reading.

Frost Point Ôëê Dew Point - (Dew Point x 0.07), when Dew Point is below 0┬░C

Example

A dew point of -10┬░C:

~-9.3┬░C (15.3┬░F) frost point

Why Frost Point Differs From Dew Point Below Freezing

Frost point is the sub-freezing equivalent of dew point - the temperature at which air becomes saturated and deposits frost directly onto a surface, rather than condensing into liquid dew, when the dew point itself is below freezing.

This Is a Simplified Approximation

This is a simplified approximation intended to illustrate the relationship between dew point and frost point below freezing - precise frost point calculations require full psychrometric formulas accounting for saturation vapor pressure over ice versus over liquid water.