It's very late in the season to plant cover crops and I'm afraid germination and growth will be minimal. Most winter cover crops are planted by mid-October with the exception of annual ryegrass, which is probably the most cold tolerant. At this point you would likely be better off mulching the soil with compost, separated dairy solids, leaves, or even cardboard or newspaper to provide some soil cover.

Or be ready to plant cover crops during the dry spell we almost always get in February. We've had pretty good luck with those February plantings if you can leave the cover crop in until May or June, by then they would provide some biomass to help build soil quality. The crops might not flower by then for pollinators, but you could leave some patches in the ground to go to flower even if you incorporate most of the cover crop earlier.

It really depends on your goals. If you are most concerned about cover and weed management for winter to early spring, I'd recommend mulching right away.