Thermometers and accuracy?

[MoreCowbellAz]

Happy holidays all - Now that my 6 year old DT is hibernating comfortably in his fridge for the winter, I use this time to make improvements/refinements for the upcoming year. One of the things I'm contemplating is the question of how close is "close enough" in terms of accuracy of thermometers? They all vary at least a little and I'm not aware of any way to know what the actual absolute "true" temp is, and if they're off by a degree or 2 does that margin even matter? I have a bunch of thermometers (mainly Acurite) and before I trust any of them I test and compare them all to try to determine which ones appear to read high, low, etc., and I make that my baseline from that, but honestly at the end of the day these are just educated guesses based on what I'm seeing among them. By all accounts I figure I'm within a degree or 2 of what the actual "true" temp is, but is there a better way to verify this, and does a degree or 2 even matter or is that just unnecessary splitting of hairs? I suspect it may be the latter, I tend to do that, but set me straight if I'm misguided and there's a better way.

FYI I've been using mainly Acurite thermometers from Lowes for some time, some are the remote sensor variety and some are the stand alone units (@Tom I got one from you when I bought that nitebox from you a couple years ago), and I've been happy with them, they've been reliable and pretty consistent, usually within a degree or 2 of one another (but again, does a degree or 2 matter?). I did have one remote sensor in the hibernation box go wonky on the humidity reading just a week ago, so I replaced it, which is what brought this question to my mind.

 

[Tom]

You can buy high dollar ones that are supposed to be more accurate, but then, how do you test those for accuracy?

In practice, I've always used the cheap hardware store ones and they have worked well enough. I do the same thing you do and compare 2 or more of them for sort of a "cross section" of readings and make my best educated guess. I also move the thermometers around to different areas to see if the temperature difference is due to location. A degree or two one way or the other is inconsequential in most cases. For brumating DTs, it shouldn't get over 50. So assuming my cheap thermometer is off by a couple of degrees, I set the temp to around 46. Then if it's really 48, that is okay. Or if it's really 44, that is okay too.