The NPS said this afternoon that the cherry blossoms reached peak bloom for the 2017 season today, March 25. Peak bloom is when at least 70 percent of the blossoms are open. I have more details on what peak bloom does and doesn't mean here.
The calculation is a little different this year. Normally it's when 70 percent of the total. But because about half of them were wiped out by the cold recently, the calculation this year is based on 70 percent of the remaining blossoms.
Want to Help Support DC's Cherry Trees?
If you'd like to help support the care and upkeep of the cherry trees around the Tidal Basin, the Trust for The National Mall has launched an Endow a Cherry Tree Campaign. Donations go to the official Cherry Tree Endowment, which will give the National Park Service additional resources to fund the care, maintenance, and possible replacement of the cherry trees. You can find more information here.
The Trust is dedicated to marshaling private support for maintaining and improving the history National Mall area. I'm not affiliated with the Trust--just an admirer of their efforts.