This study investigates the critical temperatures that separate rain and snow events by using hourly precipitation information, air and dew point temperatures. The study period was taken to be 1997-2016 for air temperatures and 2007-2016 for dew point temperatures. In the study, only the winter season was taken into account, as it includes both snow and rain observations. During the study period, 8 different winter periods were identified for different parts of the country. To define the temperature at the onset of each precipitation event, an interpolation was applied to hourly air temperature values. It is found that critical air temperature values range from 0.5 to 2.2 degrees C with an average value of 1.4 degrees C. In addition to critical actual temperature, critical dew point temperatures vary from -2.1 to 1.3 degrees C with an average value of -0.2 degrees C. As a result of this investigation, only a statistically significant relationship was found between relative humidity and critical dew point temperature. This relationship states that approximately 8-9% increase in relative humidity may cause 1 degrees C increase in critical dew point temperature.