White cotton resist well to water, but pollution and rain do not mix well:  Avoid leaving your hammock outside when it rains.

To hang your hammock, it's better to use a steel hook screwed firmly.  This way you can remove the hammock easily when it's raining.

It is possible to burry piles (8in min recommanded) and to screw in hooks.  Also it's possible to tie it to a tree or to a fence.

Our hammocks have a 10 years life expectancy when not summited to rain.