I would think the hygros would be the accurate ones, because the unit is set to 66, and the ambient is about 72. I doubt the unit would get to 57 and stay there with these factors. But I'm still hoping a wineador owner has seen this before and it's just the display being off. If things are still wonky tomorrow, I'll calibrate the hygros again (just did it a month ago) and check their temp readings. The batteries are only a year old, but they may need replacing as well.