Only down in the single digits here, but I can tell you someplace in the low 20's or teens, my compact florescents, in some of my static display, don't warm up enough to even flicker when the LE ramps them up.
Put those in a few years back for cost savings, but with only the occasional on and off, it looks like I'm out there this morning in 7 degrees changing a bulb to incandescent!