A rule for roses here in Florida: There's an inverse ration between heat and bloom size. Hot weather means frequent flushes but smaller blooms, and cooler weather results in fewer flushes but much larger flowers. In the heat of July and August, those roses in my garden that are still blooming (like my Bermudas and OGRs) have relatively small, short lived flowers that come and go in cycles of two weeks or so. These blooms also tend to be less fragrant. During the cool and dry Florida winters, the flowers are slow to form, but they are much larger, longer lasting and more fragrant.
Here's an example: Abraham Darby, a David Austin (English) rose that does quite well in my garden. A likeable apricot, yellow and pink bloom with a fruity, slightly citrusy fragance that fills the kitchen. The most recent flush took a long time from bud to flower (about a month) due to the fairly cool, December weather we've had. Darby's a wonderful rose with a significant drawback -- with one to four blooms per stem, the bush is just nowhere near strong enough to hold the blooms upright. The stems are pretty short, too, making cutting difficult. Still, if I put them in a narrow-necked vase like in the picture, they are very striking.
I complain about the difficulties of growing flowers in Florida, but where else could I, at the end of December, pick blooms like this (and, while I'm at it, pick a juicy orange)?