A light emitting diode (LED) light bulb includes a thermally conductive base and at least one LED assembly disposed on and thermally coupled to a surface of the base. The LED assembly includes at least one LED configured to generate light. A thermal optical diffuser defines an interior volume and the LED is arranged to emit light into the interior volume and through the thermal optical diffuser. The thermal optical diffuser is disposed on the surface of the base and extends from the base to a terminus on the light emitting side. The thermal optical diffuser is configured to include one or more openings that allow convective air flow between the interior volume of the thermal optical diffuser and ambient environment.