The LED lamp has an enclosure defined by a housing and an optically transmissive exit surface. A base is connected to the enclosure. The housing is connected to the base at a proximal end and diverges as the housing extends away from the base to a distal end. The optically transmissive exit surface is connected to the distal end of the housing. A LED board is positioned transversely to a longitudinal axis of the enclosure adjacent the distal end to define a first interior space and a second interior space. A passage communicates the first interior space with the second interior space. A first aperture and a second aperture in the enclosure communicate the first interior space and the second interior space with the exterior of the lamp.