I have a brand new (1 month old) Frigidaire chest freezer, model FFFC09M1RW.

I have a temperature probe in it that is connected to my weather system so that I can get alerts if the freezer temperature goes above my threshold. I also graph the temperature over time. What I'm seeing is that the freezer temp stays at -18F to -22F pretty rock solid, but about every 2 days it rises to +2 to +3F before it kicks back on again. The timing doesn't appear to be related to external ambient temperature around the freezer, and does not appear to be following any kind of schedule (its a "dumb" freezer, no user-accessible features besides coldness dial).

Does this sound like something that's as-designed? It seems odd to me because the time from -20F to +3F takes about 4 hours, faster than I'd expect the internal temperature to rise if the compressor was just not running. It takes an additional 6-8 hours to cool back down to -20F once things start cooling again.

The freezer is about half-full.

Is this some sort of defrost cycle? Or is it some sort of prevention from getting too cold?It seems to happen usually at a low temp of about -22F to -24F.

Thanks for any thoughts.