My vote is statistically extremely unlikely to affect the outcome of the election. This is counter-balanced by the extremely large impact affecting the outcome would have. I'm inclined to believe that the two roughly cancel, so that a (say) one-in-several-million chance of affecting the outcome is worth the effort of voting. But I live in California, where my vote is roughly 100x less likely than the average vote to affect the outcome (FiveThirtyEight has done this analysis, though the precise number fluctuates and has considerable uncertainty).
So then what are the effects of my vote? It nudges the statistics a little. It increases turnout, which probably increases confidence in our democracy. It increases turnout among 18-29 year-olds, probably increasing their political clout and furthering causes they support. Do I agree with them on the whole, or in particular on issues where their political clout is likely to tip the scales? I don't know. Say I vote for Clinton, it also increases her popular vote total. If she wins, it slightly improves her electoral mandate. If she loses, it slightly deprives Trump's mandate. It also increases the chance that Trump wins the election but loses the popular vote--a potentially very unpleasant scenario.
How do I measure and balance these? How is a consequentialist to vote?