I would be very surprised if any of mine were so far out, at least the modern digital ones. Where I have compared them I have found them within a few tenths of a degree of each other, but much depends upon their location. Even in a draft free home there can normally be a degree or so difference in temperature between a measured wall temperature at the bottom versus the top due to convection taking the heat upwards.goldrush wrote: Often their specs are +- a "few" degrees at the lower end. Particularly if they are "domestic" models I have tried 3 different types and they all vary by 3 or 4 degrees against a standard.
For work, I use one of those IR contact less temperature measuring guns. You just point it at an object to get an instant reading of the objects surface temperature. Point it at a high cloud in winter and you get temperatures as low as -40 C.