If you wait until summer, the difference will be greater!If you shave it now, yes, there will be a color difference between your face and scalp, but it probably won't be as drastic as in the summer and it will even out in a few weeks... or as Mike said, you can help it along with a self-tanner.
I would suggest standing outside (even it is a little cold or overcast in winter) for about 20 mins or longer each day