The study was based on the results of daily measurements (taken at 1 p.m.) of air temperature and wind velocity and average diurnal temperatures of the air at the height of 200 cm above the ground, taken during the period from 1st November to 31st March in the years 1960/1961-1999/2000. The data were gathered at the agro-meteorological station at Lipki near Stargard, situated in the central part of the Szczecin Lowlands. For the evaluation of bioclimatic conditions, the wind chill index (WCI) was used, with the scale of heat perception defined by Maarouf and Bitzos. The perception of weather conditions was assessed during winter and spring thaw and during thawless periods. The analysis showed that the diurnal values of WCI index varied from about 370 do 1523 W m-2. This made it possible to classify the days of this period within three categories of heat perception: comfortable, cool and cold, and a dominating category of perception during atmospheric thaw, independently of its duration, is cold. The appearance of atmospheric thaw is connected with improvement of heat perception, which is mainly illustrated by a decrease in the frequency of cold days and an increase in the frequency of cool days.