Some states require that you are registered to vote 30 days prior to the election. That means some folks just have a little over a month to take care of this if they aren't registered but want to vote in the upcoming election. Don't talk big politics on the boards but miss out on getting to vote because the deadline slipped up on you!
You can check the page below to see when the deadline to register is for your state.
State Voter Registration Deadlines