Sakura Simulator application - daily coverage of Japan's cherry blossom flowering time
Weathernews released a service called Sakura Simulator which allows you to monitor the current blooming situation of cherry blossoms all over Japan.
Based on cherry blossom reports submitted by users locally around Japan, you can check the current extent of cherry blossoms on the Japanese map based on actual feedback from people personally observing the trees. There are 5 different blooming levels that are reported: Bud, Bloom, Full bloom, Falling, and Cherry tree in leaf. It is also possible for you to zoom into a detailed area and observe the situation there, or compare the current situation with the one on the same day last year by looking at photos from last year.
The cherry blossom reports are submitted by users as part of the Sakura Project in the Weathernews Touch application sponsored by Weathernews, where people informally adopt cherry blossom trees and monitor the progression of the cherry blossoms.
The application is unfortunately only in Japanese. It is available for iPhone and iPad and for Android.
Weathernews is one of the most popular services in Japan for news about weather, earthquakes, etc. and features live reporting and picture submission from people around Japan showing the weather and conditions in their area, and allows commentary.
The app is Japanese-only, but if you can deal with that, or if you just want to see how the pretty flowers look: