I’ve seen that problem with temperatures displayed by quite a number of banks on the Range. Maybe the sensors are improperly housed. That is, maybe they’re soaking up warmth from the housings around them, which housings may get sunlight at times or heat from the buildings that they’re attached to.
It’s hard to tell with thermometers from a local store, too—both liquid and coil types. The liquid thermometers tend to be limited from reading very low temperatures. The coil thermometers degrade and are often inaccurate when new.
Thermistors (temperature sensors) are probably the way to go. Some of the low-cost, tiny weather stations with a few modifications to protect them from extreme temps, 100 mph spraying ice, etc., can do well, if the temperature sensors are properly housed (shielded from sunlight while not warmed by a surrounding case).
I’m in an area without a registered, local weather station, BTW, and have a few other things to do before mounting new weather monitoring equipment here. For accurate weather readings and forecasts around the Range, we would need many more weather stations. Temperatures, for example, are often radically different between my location and a location about three miles to the east (transition between patterns).
The first ten years I lived here the time and temp were always accurate. Location of sensors wouldn’t explain the incorrect time either. Since they obviously aren’t going to fix it I wonder why they don’t save the electricity and just shut it off.