The record of the blossoming date of cherry trees in Kyoto, Japan, is one of the longest phenological records climatologists have.  Historical information on the blossom date goes back all the way to 812 AD, although nearly continuous records are not available until 1406 AD.  The dates have recently been compiled into a single record, which you can see at  A graph of the date of spring full bloom for each available year is shown below.  The spring bloom is now coming almost two weeks earlier than the early historical record’s average.