A distribution transformer monitor includes a housing arranged for positioning in proximity to a distribution transformer vessel. The monitor also includes a sensor arranged in the housing, which is positioned to generate digital data associated with at least one environmental condition that exists inside the distribution transformer vessel, and a processing circuit arranged to determine from the generated digital data that the at least one environmental condition has crossed a threshold. The sensor may include any one or more of a temperature sensor, a camera, an accelerometer, a pressure sensor, and a microphone. The housing of the distribution transformer monitor may include at least one indicator legend arranged to facilitate positioning of the housing in a substantially vertical orientation relative to the distribution transformer vessel.