I typically have 3-4 thermometers in there and at least 2 hygrometers. But I was starting to get used to all the thermometers being withing .2 degrees of each other when there was forced air. So when my fan came in (specifically for my incubator, not jerry-rigged), I didn't think I'd need multiple... silly me, right?
Lesson learned.
That seems to be the case haha, the motto should be, never trust a thermometer.