How often or even if you need to water at all will depend on your weather. Here in the moist PNW, once fall hits and the leaves begin to drop, I never need to water anything outdoors.......and that includes all my containerized maples as well. We get as much natural irrigation as necessary from Ma Nature :-)

However, if you live somewhere where it tends to be quite dry in winter, yes, you will need to water periodically. Typically since temperatures are lower in winter, soils do not dry out as rapidly as they do during the growing season. And trees in dormancy do not need the same degree of hydration as they are not going through any transpiration. But you do not want the soil (and therefore the root system) to dry completely.

Check the soil periodically as may be determined by weather conditions. If very dry to the touch down to the second knuckle, then provide water. I can't think of many places in your zone where you would need to do this more than a two or three times during the winter months. The soil should be just moist to the touch.