Date by which 100 plants flower fluctuates wildly

Yesterday was lovely, and the Phactors ate dinner on the patio with friends.  The center piece was a Caesar salad with fresh romaine lettuce and a dynamite home made salad dressing (a Sheila Lukins cookbook recipe). Two dark pink tree peonies were in flower as well as the one flower the squirrels did not eat was open on the big-leafed magnolia.  One of the metrics TPP keeps is the date by which the first 100 plants in our gardens flowers (out of pretty close to 300 flowering plants). This year the 100th plant was magnolia vine (Schisandra chinensis, a basal angiosperm!).  The database is now in its fifth year and the total lack of a pattern or trend or consistency is quite evident.  In 2012, the 100th plant flowered on March 25th. Sorry, this isn't intended to mock readers waiting for the ice to melt out of the Bay of Fundy. Last year the 100th plant to flower wasn't reached until May 5th, and this year it was on May 7th!  So in just 5 years of data the earliest and latest date on which the 1st 100 plants flowered differs by 43 days!  Welcome to a continental climate folks - highly variable, highly changeable. Now we be needing some rain, and please without any twisters.