A thermometer having a short cup-shaped housing, an arcuately slotted top and an open bottom, the thermometer being used for sensing temperature on the surface of objects or room ambient temperatures in the event said surface temperature approximates the room ambient temperature. Extending into the inside of the housing is a centrally located member. The inside end of a bi-metallic element is mounted inside the housing eccentrically with respect to the centrally located member. A free end of the bi-metallic element is provided with a flanged or headed pin which is adapted to be captured by and float within a channel or slot extending radially outwardly from the outer edge of the annular ring such that expansions and contractions of the bi-metallic element are transmitted to and produce rotation of the annular ring. The channel portion extending radially outwardly from the annular ring has a flag member affixed thereto which is adapted to traverse the arcuate slot in the housing and register against temperature indicia on the outside of the housing. The thermometer is surface mounted by means of either a centrally located magnet or a fastener located centrally of the housing and the annular ring.