An LED lamp includes a heat sink having a base and a plurality of fins extending from the base. A plurality of LED modules is thermally attached to the base of the heat sink. A lamp frame surrounds the LED modules on the heat sink and is hermetically mounted to the heat sink. A lens is hermetically attached to the lamp frame and covers the LED modules. The fins includes a plurality of first fins extending from a first face of the base of the heat sink, and second fins extending from a second face of the base. The LED modules are located between the second fins. A pole has a top end engages with the lamp frame. The pole is used for mounting the LED lamp at a desired position, for example, a sidewalk of a street.