The freezing point of vinegar is 28 degrees Fahrenheit, or -2 degrees Celsius. Its freezing point is below that of water because of its acidity.
Vinegar is made up of water and a chemical known as acetic acid. On its own, acetic acid would freeze at 60.8 degrees Fahrenheit, or 16.6 degrees Celsius. However, because of the interaction that acetic acid has with water on a molecular level, the freezing point of the acid when it is combined with water drops dramatically — so dramatically, in fact, it drops below water’s normal freezing point of 32 degrees Fahrenheit or 0 degrees Celsius.
It should be noted that this freezing temperature is not necessarily concrete. It can fluctuate by a few degrees here and there depending on the acidic concentration of the vinegar and the overall density of the solution.