An electronic sign includes a planar lighting module emitting visible light. A cabinet supportingly engages the lighting module. An air chamber is between the cabinet and the lighting module. A vertical partition is within the air chamber and extends between a bottom wall and a top wall of the cabinet, and between the lighting module and a rear wall of the cabinet. The partition divides the air chamber into first and second sections. An electric fan is within the cabinet and transfers air from the first to the second section. The cabinet and/or the lighting module include a plurality of throughholes fluidly interconnecting the air chamber to ambient air. A first subset of the throughholes are more closely fluidly connected to the first section than to the second section. A second subset of the throughholes are more closely fluidly connected to the second section than to the first section.