A thermometer housing of a generally cylindrical configuration is arranged for floating reception within a bathtub, with the thermometer housing including a top wall divided into a first and second semi-annular indicator surface, with an indicator arrow operative through a bi-metallic spring arranged for deflection from the first to the second indicator surface upon bathtub water elevated to a second zone of temperature to be classified as inappropriate for bathing. A stabilizer weight member is mounted to the bottom wall to maintain alignment and emergence of the housing side wall within the associated bathtub body of water.