For me it was Feb 1st. In the PNW the temperature gets to freezing but not much more so no drama as it's FWC. It was just open the petcock, close the raw water inlet, pull the choke and crank about 10 secs... Life! Oh, and open the raw water.
Then turn the heater on.
I never winterize, but the water get to 46F at the coldest I'm ever measured.