The day the electoral college votes must be the same throughout the U.S. The day the electors are voted for is up to each state's legislature unless Congress says otherwise.
The point is it states one day.
I assume you are all for this early-vote junk? Why did this never happen for 200 years, then, if its OK?
How long do we allow people to vote, such that they may be dead at the due date (this really applies to mail-it-in, too)? Does it make sense to allow someone to vote in September who is dead at the time of closing?