Most of the data was painstakingly collected and analysed by Prof. Aono and his collaborators: http://atmenv.envi.osakafu-u.ac.jp/aono/kyophenotemp4/

The full-bloom date for 2023 (yesterday: the 29th), was confirmed by local resident and friend, Aya. (bc the data refers to a very specific species and location, they do not match official JMA reports)