You need to keep your fridge between 33°F and 38°F to prevent frost buildup and keep your food safe.
A liquid filled thermometer is the way to go here. They are pretty darn accurate, don’t need batteries, and you don’t need the speed of a digital. The CDN is low profile and has hooks to hang on the wire racks. Get two, one for the freezer, too.
Where to buy (buying from this supplier supports this website):
Bill McGrath - Bill McGrath is AmazingRibs.com's Thermometer Maven. He has sophisticated equipment, an electrical engineering degree from Cornell University, and an MBA (almost) from UC Berkeley. Despite being mostly retired, he is still the person responsible for developing and updating all of ExxonMobil's training modules.