I'm assuming you mean presidential election. But there are some state and local elections coming up this year. In fact, today is National Voter Registration Day in the US. (There's a specific day to remind people to register to vote or update their registration as needed.)
The day itself is more just to remind people to register to vote. Registering to vote can be done any day of the year, though there is a deadline if you plan to vote in a certain election. You don't need to register more than once in a particular state, though you do need to update your registration if you move to a new address.
The deadline for registration varies by state. For my state, it's 22 days before an election. But, at least in my state (this isn't the case in every state, but it's getting there), even if you don't register by the deadline, you can still fill out a voter registration form and vote using a provisional ballot (meaning it will be counted later that week after your voter registration has processed) on election day.
Basically, National Voter Registration Day is used to avoid a lot of headaches for everyone involved.
Just get rid of the nonsense and learn to be civilized you heathen! I think it's time for Europe to colonize America to civilize them again /s
All ballots are counted on election day here. I know because I was a Poll Clerk in an election. The Deputy Returning Officer (person in charge of the polling station) has final say on same day registration and then all ballots cast are counted on election day.
Or better yet be like Colorado with automatic registration.