technical botany type questions

All,

(because I’m stalling doing real work unfortunately):

Two questions from two completely unrelated sources/issues/parts of the country, both “weather” related:

Strong coloration in the Deep South is a bit of a joke – we don’t get much. Someone once made a passing comment that if the temps weren’t cold enough at the exact time when the flower is forming, the pigment compounds don’t form so you don’t get color.
Could someone really lay this out, from soup to nuts, expounding upon cold hours needed at specific points in flower bud formation, etc. -?

This really warm spring with one or two serious cold drops in the middle did really squirrely things to the daff season; some flowers were greatly impacted others not. Some sped up bloom time by 2 wks, some by 4 wks, others (the more late mid’s) ran about on time or just almost a week early. HOWEVER, I had a clump of singles in full bud completely blast – NEVER seen that before. In Tallahassee, some patches and some cultivars almost didn’t bloom at all – things that have been regularly blooming fully for a decade or well better. This happened in Early to Early Midseason flowers (sorry I don’t remember cultivar names right off).
Could someone elucidate why severe temperature fluctuations would start then stop the blooming process -?, and why it doesn’t “restart” (or the trigger mechanism re-trip to restart the blooming process) in some of these highly reliable cultivars?

Thanks in advance~

=s