A gas burner for cooking appliances employing a ring of main flames for cooking, and a ring of simmering flames for heating. A first chamber contains the gas and primary air mixture for feeding the ring of main flames through a circumferential wall with a plurality of radial apertures. The chamber contains the gas and primary air mixture for feeding the ring of simmering flames through radial passages. The chambers are superposed, and a separator plate is interposed between the chambers. A cover rests on the separator plate and the radial apertures are defined therebetween. The cover extends beyond the passage and shields same from ambient conditions.