Last weekend was peak bloom.
But there are actually multiple species of cherry trees out there and they don't all bloom at the same time. The difference is on the order of 10 days to 2 weeks.
The later blooms are better seen in the Kenwood area of Bethesda. But I'm not sure how transitable that is. The Washington Post usually has a cherry blossom guide somewhere on their web site.
By the way, in the increasingly likely event of a government shutdown, the cherry blossom parade won't happen, but the Japanese street fair (which is privately funded) will still go.