Abstract: A cold temperature light fixture comprises an insulated housing having one or more ballasts and plural lamps to retain heat within enclosure so that ballasts and lamps start up more rapidly, and greater light output is obtained. The fixture may be operated in selected configurations and may include secondary heating elements within the fixture to warm ballasts. In one operating configuration, one or more of the ballasts is always energized and one or more of the lamps is preferably at least partially illuminated in an off mode. A sensor is operable to switch the fixture between the off and on mode, in which all ballasts are energized and all lamps illuminated.