If temps are forecast to hit freezing or below, it's always best to disconnect hose, both from rig and water source.
Experienced a freeze one nite that came unexpectedly...wasn't forcast to get below around 40.
Hit 30 and hose froze, but worse, the water inlet that hose connected to on rig...when water froze, the fitting cracked, basically making it impossible to use water connection.
Luckly I carried a spare and was able to repair later that morning...3 screws and a hose clamp.
Lesson learned...freeze....disconnect water hose !!!