Not all light fittings are designed to be used in situations where they are exposed to the elements, such as the outside of buildings. It is always important to check if a product is weatherproof before selecting it for use in an exposed situation. IP or Ingress Protection numbers are used to specify the degree of protection provided by the enclosures of electrical equipment, such as light fittings. These ratings are always composed of two numbers with the first referring to the degree of protection from solid objects such as dust and the second, the protection from liquids. An IP65 rating for a luminaire means: the 6 indicates there is no physical access to the hazardous parts by solid objects and the enclosure is 'dust tight'; the 5 indicates that the enclosure will protect the interior from the effects of water projected from any direction; ie hosing and powerful rain. Remember - if no IP rating is specifed then it cannot be used outdoors, unless in a fully protected area.
Ingress Protection Rating Diagram