Starting Hugels in winter?

I was wondering with the milder winter we have been having in our area so far can Hugels be started in winter? Will there be a problem as the cover crop won't be growing till spring?

The sooner the better! I personally wouldn't worry about a cover crop if I was building one right now. Just make sure to mulch the heck out of it (use plenty of whatever you can get your hands on 8-12 inches deep) to help hold the soil in place and soak up as much moisture as you can. This spring you can pull the mulch back and plant your crops (or spread cover crop seed), then wait for it to take off.

I am in total agreement with Dave. Get them built (at any time of the year you can in fact) then cover them with plenty of mulch until your ready to plant something.
If you have the resources, you could put up a tunnel over the new mound and that would let you get something growing much faster than waiting for spring planting.
My plans for this next year will include setting up two growing mounds that will be shaped for tunnels to be placed over them in the future. This will let me grow crops that I normally have to wait till the middle of march to plant.