Get him a cool headlamp helmet and turn it into a nighttime scavenger hunt!
Does he have a torch? My toddler loves going out in the dark with her torch.
Warm coat, hat and a torchlight. My son is the same. He LOVES being outside and after he finishes nursery at 6pm, we have a snack (he has dinner at nursery) and then we head out for an evening walk. He looks forward to this everyday and it's become routine. We hunt for red cars (his fav colour), police cars, and other fun things he decides to point out that day. It also tires him out ready for bed 😁
Warm coat and still head out. My eldest was like that. I’d be lucky if I got him home before 6.30pm no matter what time of year. I’d recommend getting a reflective winter coat so they are visible to cars just to be on the safe side.