A normally red state, Arizona has emerged in 2016 as a presidential battleground: FiveThirtyEight's "polls-only" forecast gives Clinton a 49.8 percent chance of winning the state compared to Donald Trump's 50.2 percent.
Clinton is scheduled to campaign in Phoenix, Arizona on Wednesday November 2, her campaign said.
Despite the tight presidential race, Sen. John McCain is likely to win reelection in the state, according to polls.
The last time Arizona supported a Democratic presidential candidate in the election was Bill Clinton in 1996. Before that was 1952.