I think you mistake the Sun's journey through darkness with the season of winter.
Yes it's a fact that days got shorter nights got longer to this point and from now on the process will be on the reverse. But Winter is still just starting, it will be at its height in January, and the wolves of frost can still return to eat the pig of wealth in April.
We're still going from the bounty the Summer gave us. Should be plenty of grain, and pigs (reindeer for you, horse for us) are still butchered around this time. The pantry is full and everything is cozy. Depending on how the next couple of months go, the start of Spring might need a self-sacrifice.