I don't think there is a uniform answer to your question - it will depend entirely on the climate and current weather conditions. For example, in my zone 8 PNW climate, I haven't watered any container plants since early October and unless we have a VERY unusual winter, it is highly unlikely I'd water again until April. Even if we go a week without rainfall, temperatures are cool enough that evaporation is minimal and there simply is no need for additional irrigation.

Your climate may be significantly different and quite dry during the winter, however, unless temperatures are high, evaporation is unlikely to be a big factor either. What you DON'T want is to have the containers dry out - you will need to water often enough to ensure this doesn't happen but not so often or as thoroughly as to keep the soil saturated. Evenly moist is the key :-)

Why does a plant need water? For photosynthesis and to keep the roots from drying out. The equation for photosynthesis basically is:
CO2 + H2O + LIGHT = SUGAR + O2
If any of the items on the left side of the equation is limiting, photosynthesis will slow down or stop. If so the other two items on the left side will be in abundance. For example, it's fall now; almost winter. The plant is getting less light. So, if we keep watering as much as we did with a lot of light, it's too much water. You can get root rot. There is a balance. Some days cloud cover could cause you to water less. Plus, if the plant is dormant, it doesn't need water. It will only harm it. Of course, a little is good to keep the roots from drying. But, the roots are not taking any water in.

I don't believe it is quite that simple - photosynthesis is not the only reason plants require water and while their needs may reduce in winter, they are not totally eliminated by dormancy. There is a lot of stuff going on internally and roots are never completely dormant. Adequate winter irrigation is one of the reasons plants become properly cold hardy. Moist soils tend have higher insulating factors than do dry soils. And more plants are lost to winter drought/lack of watering than are lost to winter cold. That doesn't mean one should water regularly in winter, only when conditions warrant to prevent soils from drying out completely.

No living system can start itself (in spring). In order for a tree to live through winter, it needs a continual supply of water and nutrients to keep it viable. Respiration is the driving force behind winter water uptake and is needed to provide energy and to keep cells alive.
Unlike photosynthesis, which is seasonal in most climates, at least some respiration occurs at all times (even during the dormant season).

Translocation (water & nutrients), is a major physiological process and is necessary for respiration to function properly. Without the "piping" system of translocation, moisture and nutrients would not reach tree organs, respiration would stop, and the tree would die.

So, I agree with GardenGal except that I might differ in the area of irrigation's effect on cold-hardiness. Plants need little water during the dormant period - just enough to keep cells hydrated and energy (to keep systems orderly) flowing. Drought-stressed plants are normally substantially more cold-hardy than well irrigated material. However, if you are over-wintering a plant that is not being subjected to temps that will make it "borderline hardy", it's best to forget the advantage of drought-stress in favor of a less risky plan of "barely damp", which also means forsaking the policy of deep watering - a sure problem causer unless you grow in a very fast medium.

Check soil on dormant deciduous trees at the drainhole. When soil feels dry there, throw a handful (or two) of snow on the dormant plant.

Al