A lamp includes a bracket, a cover and a lamp body pivotably engaged with the shaft. The bracket includes a shaft with a flat top surface. The lamp body includes a first lateral portion and a second lateral portion. The lamp body defines a channel with a flat top surface. The cover is mounted over the second lateral portion. When the lamp body is at a first position, the top surface of the channel engages the top surface of the shaft. When the first lateral portion of the lamp body is subjected to weight of snow/ice accumulated thereon which is beyond a set value, the lamp body rotates around the shaft from the first position to a second position to enable the snow/ice to fall from the first lateral portion.