However, care should be taken to ensure all of the wood you are using is kiln dried. Kiln dried wood has been dried in a special furnace and is more dimensionally stable and less likely to warp and crack with time. Generally yellow glue is the best. Titebond II works well and can be used for outside furniture. The ultimate glue for external use is polyurethane glue such as ProBond.
Polyurethane glues tend to be a little harder to work with and cost more.
One of the most important things to remember is that if the glue is too thick it won't squeeze out of the joint and allow the joining pieces to touch. Also remember to use new glue. If the bottle is too old to remember when you bought it, get a new one. Glue does have an expiration date and will fail to hold-up under use. Be sure to use only enough to cover both sides of the mating pieces.