Flight safety depends on a number of meteorological factors, including icing. Forecasting of aircraft icing implies taking into account only the meteorological conditions; therefore, “icing possibility” is forecasted. The next step in forecasting techniques is a technology of predicting the current state of weather — nowcasting. This technology requires continuous input measurement data with small time steps. These requirements can be met by using atmosphere remote sensing. A new methodology is proposed for detecting possible aircraft icing areas, which is based on remote measurement of air temperature profiles in the lower kilometer layer and the total vapor content of the atmosphere. The total vapor content is measured using an RMS-1 radiometric system. The data series of air temperature profiles and the total vapor content of the atmosphere in the area of St. Petersburg airport (Pulkovo) are analyzed for the period from November 2018 to March 2020. The distribution patterns for temperature and total vapor content typical for the onset of icing are determined.