Question about Nikon AF-S Nikkor 16-80mm f/2.8-4 E ED DX

To give a more accurate answer than the helf wrong one from David Lim:

According to nikon NO lens is proofed against any specific amount of water or anything else. Not even the supertele's, so if you ever have an issue regarding moisture it isn't officially covered but Nikon in switzerland is extremly forthcomming in that respect.

To this lens specificaly I wouldn't trust it in rain, since it's a zoom that extends and sucks air in, when zoomed in.
However it's build quite robust and some dropplets won't hurt it, if you watch out, that they aren't sucked in and it should last you quite a while.

Note: When I talk about rain, I mean really nasty rain combines with wind in which most people won't photograph anyway.

Yes, this lens is weather resistant.