When spring comes, millions of Japanese happily turn their thoughts to one thing: When will the cherry blossoms start blooming?

"Sakura" cherry blossoms, a symbol of Japan, last only about a week, so arranging a sakura-viewing party with friends or family at just the right time is a matter of keen concern for many in pursuit of this particular seasonal joy.

Though generally off by only a few days, the Meteorological Agency has often been criticized for inaccurately predicting the arrival of the cherry blossoms.