Taxes when selling 1 year to the day or month

[Matthew Conner]

I understand that the tax rate when selling a rental is based on less than or greater than 1 year. But where is the line drawn? If I closed on a rental August 20th last year what would be my soonest closing date to take advantage of long term capital gains? August 1st, August 20th, or does it have to go into the next month in September?