The IP rating of a fitting determines how water and dust proof it is. The IP rating will be made up of 2 numbers, and is written as IPXY. The first number (X) will be the dust proofing the fitting has, whereas the second number (Y) will be the waterproofing on the fitting.
Because of this, having an higher number may not lead to something being more water proof. For something to go outside, it has to have at least a 4 for the water rating - this means that the fitting is suitable to go outside as long as there is some protection above it, whether it be a roof or eaves to cover the fitting. Anything with a 5 or above for the waterproofing number means that it can go outside fully exposed to weather, and anything 7 or above will let the fitting be submerged for a short while in certain cases.
If you have any questions about whether a light or fan will suit your outdoor needs, send us a message and we'll do our best to find something that will work for you.