Good question but the answer depends on your local winter conditions. It would be best to get someone in z6 and your region to respond but here is a general response.

When direct sowing some of your seeds may germinate now, others may need winter freeze & moisture to break dormancy so you would see them in the spring.

If the seedlings are northern hardy they should make it through the winter even if they germinate now so long as they have enough time to get good roots established before freezing weather sets in. That is also a dependency on your local region. Since it can take several weeks for seedlings to sprout & then to develop true roots you need to calculate if you have enough time before frost would drive them into dormancy.

In my area, winter is our driest season with very little moisture but too cold to use a hose to water. Because of that I would only direct sow after freezing weather sets in so they won't sprout until spring or else sow in the spring to make sure the seedlings have plenty of root developed before they have to go through their first cold/dry winter.

No expert here but I think the secret to winter sowing is to wait until the ground freezes BEFORE you sow if going to plant now. The reason being if you plant those seeds now, they have about enough time to just sprout and then it freeezes and they die because they were not big enough to be established before winter. So you would have wanted to plant them much earlier. Since that wasn't done, waiting until a freeze means that the seeds will not sprout until spring and that would be good.

The people I know who sow their seed directly outdoors in Ohio ( zone 5 ), wait until Thanksgiving. That way, they don't germinate until spring. Not sure about zone 6 though.