Yeah, get a second thermo.
I have a
$15 deal from the local hardware store that has a remote probe (made for little ole ladies to check temp indoors and outdoors). Best feature is a min/max feature so I can see how warm/cold the kegerator or fermentation fridge gets over a 24 hour period.
I also have some
$8.99 probe thermos from the pet store (look in the reptile isle). I find them very accurate and dirt cheap.
Having a couple of cheap thermometers around will tip you off when one of them is out of whack. I learned that from keeping a reptile (Bearded Dragon), where a bad thermo could fry the little bugger. At nine bucks a piece, buy three and litter them around your fermentation space. But at least one min/max thermometer is worth the $15-$30 investment.
Prost!
jacbop
Midland, MI