I had never had plumeria in bloom in the winter time until I moved a half dozen mature plants into my S room. The Celadine v. Ramsey (I don't know how to label this one properly but its flowers are quite a bit different than my "typical" Celadine plants. I just call it my "variation".)
I see that the winter-flowering is different than the summer-flowering. The flowers are still about twice as large as my typical Celadine flowers but there is way less yellow on the winter version. The fragrance is the typical Celadine fragrance though. @Dutchlady1
tells us all the time that flower color is altered by the growing conditions (mostly heat/sun exposure), and this is certainly true with this particular Celadine.
It will be interesting to see (if K's Fuchsia Fantansy and DD's Delight bloom in the summer months) whether my two seedling's flower colors will be more intense than their fall/winter flower colors. I thought their colors were pretty spectacular during their fall/winter blooming.
August, 2014 (comparing typical and var.)
November, 2015 - same plant
February, 2016 - same plant