The spectroscopic characteristics for a single-molecule in the vicinity of a metallic structure are studied as a function of the substrate temperature via a phenomenological model. Emphasis is put on the role of the surface plasmon excitation of the structure and its variation with the change of temperature. From the emission characteristics such as the decay rates and frequency-shifts of the molecule, it is concluded that such effects should be accounted for in certain recent experiments in single-molecule imaging using metallic tips. In addition, from the photoabsorption line-shape of the molecule, it is speculated that certain surface-enhanced photochemical reactions under realistic catalytic conditions may indeed be feasible, provided that other complications to the surface processes can be put under control during the variation of the substrate temperature.