ShowerThoughts

Refrigerators tend to be surprisingly efficient. The cold substance inside them helps keep them cool, we've learned a lot of little tricks to help people keep the doors closed (before ice makers people basically left the freezer open while scooping ice into stuff), and we've just gotten better at design and insulation.

Paradoxically, they can sometimes work less efficiently in the cold. Not because of how refrigeration works, but because of how motors work. The oil in the compressor can get thicker, and the motor has to push harder to work.
That's why some advertise as "garage ready". An efficient compressor running gently for longer can use less energy than an inefficient one running for a short time, and being too cold can give you an inefficient compressor that runs for too long.

Then the compressor locks up, stops cooling entirely while churning power grinding at nothing while your food coasts up to the ambient temperature of the environment and a dead overheating compressor.

I'd assume that the outside freezer uses more energy in the summer, as it gets hotter outside than inside the house. So over the year it middles out.

In the winter I often cool down my cooked food outside before putting it in the fridge. But for long term storage you have to have a careful look at the weather forecast, as it could be -10° during a clear night but +10° the next day. In the summer I put my cooking pots in a water bath to cool them down quickly before putting them in the fridge.