I got caught a couple of times were I needed to re winterize.
yes it makes a difference if it is going to be 32 or below for SEVERAL hours or days. In Florida and most of the south it usually is only a couple of hours right before dawn. But for me it's not worth the chance of having to replace any of those dang small plastic water hoses that break in an RV.
I just buy a couple of bottles of pink stuff and pour it into the fresh tank and run the water pump open all faucets till they run pink. A couple of bucks for insurance is worth it to me.