History shows that many elections have been impacted by weather on election day. Evidence suggests that one inch of rainfall on election day will reduce voter turn out by about 1%. This is statistically significant, especially if the electoral race is a tight one and just a few votes one way or another could decide the outcome.
Since Tuesday's weather is expected to be VERY pleasant, it looks like mother nature will not be playing a role in the outcome. That being said, some believe that nice weather brings out more voters than would usually vote, thus also having a marginal effect on the outcome.