The Chicago "L" system has most of its platforms outdoors. During the cold season, the platforms have semi-sheltered areas with overhead heat lamps, activated by a pushbutton for a timed interval. Sometimes, near the lake, we get a cool snap in August, and it is amusing to watch the teenagers from suburbs that don't get the Weather Channel, dressed in shorts and T-shirts, pushing the button (despite the label that specifies the active months).