Celsius and the Fahrenheit are the two well-known measures of measuring the temperature be it for the weather or for measuring the temperature of any other object. Now there are two levels of the measures, which decide the freezing point for the weather both in the terms of the Celsius and the Fahrenheit.
In terms of the Celsius 0 degree Celsius is the temperature when the water actually starts freezing, and in terms of Fahrenheit, the freezing temperature is considered to be 32 Fahrenheit.
So, this is the point of temperature where the weather has to be in order to be called the freezing temperature. Any level below this freezing temperature the weather will still be known as at the freezing temperature.