An Autumn Dilemma: Gingko Trees Don't Want To Let Go!

It's been over week since I saw the first gingko tree change color. And each day, on the roads, on the lanes and in the neighborhoods I pass by everyday, I see those trees slowly succumb to the invasion of the fall colors: orange, red or yellow.

                       (The very yellow Gingko trees behind 
                                  Gyeongbuk Palace)

But today, when I made my way through the Hannam-dong lane in my neighborhood, which is full of gingko trees, I was surprised those trees seem confused as to whether they have to finally give in to Cory yellow or not.

               (The confused Hannam-dong gingko trees)

Even in the Seobinggo Street leading to Yongsan Station, those gingko trees couldn't seem to decide, too.  In the past, they all turned yellow at the same time, as if in one synchronized yellow airbrushing!

                (Green on the left, yellow on the right)

But this time, what's wrong?