Why does my dog seem hungrier in winter?

Winter hunger is usually a mix of three things, and only one of them is about calories.

The first is boredom. A dog who normally gets an hour of sniffing and running is now getting fifteen wet minutes, and that leftover energy goes somewhere. For a lot of dogs it goes into hanging around the kitchen and staring at the pantry. Food becomes the most interesting event of a very dull day.

The second is routine. Dark afternoons make the whole house shift indoors earlier, so your dog is simply near you and near the food more often. More opportunities to ask, more chances someone gives in.

The third is genuine extra need, and that mostly applies to dogs spending real time outside in the cold. If your dog is working, kennelled outdoors, or already on the lean side, some extra food is fair.

The fix for the first two isn't more dinner. Scatter their kibble across the lawn or a snuffle mat instead of using a bowl, split the daily ration into two or three feeds, and add five minutes of training. A dog who has used their brain settles about as well as one who has run five kilometres.