From January onwards you can agonise over the continually shifting and never completely predictable answer to your “when should you visit” question using websites such as this one:

https://s.n-kishou.co.jp/w/sp/sakura/sakura_top.html

Edit to add - you might want to keep your eye on this page in particular
https://s.n-kishou.co.jp/w/sp/sakura...&code=19370006