Precise humidity measurements conducted with a chilled-mirror hygrometer (CMH) in the frost-point range require the determination of the condensate phase on the sensor’s mirror. Undetected supercooled water (SCW) on the surface of the mirror can lead to an error in frost point reading of up to 2K or more. A recent trend in CMH design is implementation of supercooled water detection or elimination abilities. Elimination of SCW can also be performed manually by cooling, though with some concerns regarding the reliability of the process and the reproducibility of the frost-point measurements. The purpose of this article is to present the possible automation of this process without compromising the instrument, especially in the case of calibration standards lacking elimination ability, when a long and valuable calibration history cannot be jeopardized. At the same time, the purpose of this investigation is also to study the reliability of automation and the effect of the process on the reproducibility of frost point. A special control device was developed to upgrade the instrument’s control loop without electrically compromising the instrument itself. In order to assess the SCW elimination process by cooling and to determine its optimal parameters, comparisons were conducted against the primary dew-point generator to obtain a stable environment. Our experiments have proven the reliability of the automation and the reproducibility of the frost point was within 0.012°C.