A streetlight includes a light-emitting diode and a passive cooling system. The light-emitting diode is in thermal engagement with the bottom of the cooling system. The cooling system has an upper cooling chamber and a lower cooling chamber displaced from the upper cooling chamber. A thermal flow circuit extends through a domed chamber, the upper cooling chamber, a return passage and the lower cooling chamber. The domed chamber is inside the lower cooling chamber in thermal engagement with the bottom directly over the light-emitting diode and has inlet channels in thermal engagement with the bottom and an outlet to the upper cooling chamber.