Depends on where you live, of course - do you intend to use it during a cold winter (a real treat, if you can stand the walk) - do you have it completely outdoors, or on a deck with some covering (screened-in, glassed-in porch?) -
What is actually involved with winterizing a hot tub? I know that the folks who manufactured ours recommend strongly that the tub should not be drained (for example) for the winter.
I live in northern Wisconsin and I use mine all year around - except maybe in mid summer when it is already too darn hot! It is outside and sits a few feet from the east wall of the house with no other protection.
As Classy1 mentioned, using the hot tub in the dead of winter can be a real treat - except that getting in and out is occasionally an adventure!
We have already been below zero, which isn't bad in the tub, unless the wind is blowing.
I think the term winterize is used for pools and spas that are shut down for the winter. If you plan to use and operate the tub this does not apply. Just be sure to keep the water warm enough that it does not freeze. Water freezing in the plumbing pipes could cause real damage.