weather protecting a sequoia bench

[Bodgit & Sons]

I was recently given a chunky rustic sequoia bench. The wood has been cut and air dried for 15 years so has turned mainly grey, losing most of its reddish pink colour. It is currently in my garage because i don't know how to protect it from the elements. I would like to be able to leave it outside all year and for the finish to look natural. Can anyone please suggests something suitable to weather protect it.

Thanks Dave