Compact fluorescent lamps/lightbulbs (CFLs) can be used in an outdoor application, but there are a couple of considerations.
Use a product that is specifically labeled on the package "for outdoor use." A CFL can last between two and ten years (check the hours on the package), and the metal used on the screw-in base can rust in place if the bulb is not designed for moist or damp conditions.
Consider the outdoor temperature of the location. If you live in a cold climate, check the package for the minimum service temperature. CFLs operate best in warmer temperatures and require a minimum outdoor temperature to start reliably. Most lightbulbs begin illumination and then brighten as the bulb warms up.
Additionally, if compact fluorescent lighting is used for outdoor security lighting, a fixture with a reflector can provide more light to the area.
