25/03/2025
It’s that time of year again—sakura season is officially here! 🌸 But have you ever stopped mid-hanami selfie and wondered, who actually decides when cherry blossom season starts? Spoiler: it’s not your Instagram feed.
The Japan Meteorological Agency (JMA) is the official sakura timekeeper, and they don’t just eyeball random trees in the park. They monitor a single, VIP cherry tree (標本木 / hyōhonboku) at Yasukuni Shrine in Tokyo. When five or six blossoms pop open on this tree, JMA declares “It’s sakura season, folks!” When about 80% of the tree is in bloom, that’s the green light for peak hanami madness—aka full bloom (満開 / mankai).
Now, why this tree? Originally, JMA tracked blooms at their own headquarters, but in 1964, they moved to a new location and no longer had a suitable cherry tree on-site. So in 1966, they picked a Somei Yoshino tree at Yasukuni Shrine as their official reference tree—close by, well-maintained, and perfect for long-term observation. Ever since, this one VIP tree has been calling the shots on Tokyo’s cherry blossom season.
Now you know who’s really behind your springtime Instagram feed!
