| Dear slippery,
Paphs and Phrags generally differ in their temperature preferences though there is a fair bit of similarity.
Phrags are all intermediate growers. While night time and seasonal demperature differences are typical, Phrags aren't like Phals in that they must have a 10-15F day night temp differential. Having said that, Phrags do seem to bloom seasonally. The vast majority of mine bloom in winter.
Paphs are different. Many of the hybrids bloom whenever they bloom: spring, autumn, just whenever. Others, especially the species, bloom seasonally and some of them, especially those in the Parvisepalum section (armeniacum, micranthum, delenatii, etc) must have a cold winter in order to bloom. So Paphs are a bit all over the map with respect to their need for cool temps.
At risk of slightly overgeneralizing, I'll summarize with this more specific answer to your question: Neither Paphs nor Phrags really need a day/night temp drop to bloom (they're not like Phals in this respect) but some (especially the species) do grow and bloom on seasonal cycles which naturally involve gradual decreases in temps in autumn and winter months.
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