Cherry blossom timing varies a bit year to year, based on weather etc and is usually updated early-mid March for more accurate timing.
DC/MD/VA weather in Spring is anyones guess but it is rarely hot in early Spring.
It can be warm in 70s- low 80s.
Agree with BCSnob---The Arboretum is great for blossoms and more.
There is much more to see and do in the area than most realize. Take the time to do searches based on things you enjoy.
Dont forget Monuments and not just the top 5 !!!
One of my favorote things: drive downtown in the late eveningto arrive at the Memorial of choice... as its starting to get dark. Google Monuments at night.
See the Monuments lit up. Many are a moving experience.
If you can spare the time, give youreself an extra day or two.