The National Park Service has announced peak bloom for Washington, D.C.'s famed cherry blossom trees will occur between March 31 and April 3.
If you've never experienced this, I guarantee it's well worth your time to visit at the peak.
When I was at the Pentagon, I used to do my lunchtime run in that area (across to the Lincoln Memorial and Tidal Basin) and at cherry blossom time it sometimes seemed like you were in another place entirely. Absolutely delightful.