Why does frost keep building up in my freezer?

Why we start there

Air is drier here than at the coast, so recurring frost points at the circuit rather than the gasket.

What happens next

There is one local exception. Evenings in this valley bring cooler, damper air in from the west, and a freezer in a garage or a utility room that opens to the outside takes a daily dose of it that a kitchen unit never sees. Garage and utility-room freezers deserve their own answer here, because so many households in Temecula and Murrieta keep one. A cabinet outside conditioned space lives through the full daily swing instead of the kitchen's steady conditioned air: a long hot afternoon, then a sharp drop overnight, every day for months. That means far more compressor hours, a condenser loading quickly in a space that gets opened to the driveway daily, and a drain line that freezes and thaws rather than simply staying frozen. Some frost in a garage freezer is normal and some of it is a fault, and telling us which one you have starts with telling us where the unit is standing.

If you can bear it, leave the ice where it is and call rather than clearing it first, because where the ice has formed tells us as much as the fact that it is there. An evenly furred coil is a defrost failure. A heavy build in one corner near the door is a seal or an alignment problem. Ice sitting on the freezer floor with a clean coil is a blocked drain. Ten seconds of looking before the scraper comes out routinely saves a second visit, and on a cabinet that has been running warm for weeks it also tells us roughly how long this has been going on.

If that matches what yours is doing, say so when you call — it decides which parts come on the van.