I have always thought of it as a warmish grower. When bred with Den. cuthbertsonii, one gets Den Aussie's Hi-Lo, one of those Den cuthbertsonbii look-alikes that is forgiving of warmth. Baker gives its elevation range in Papua New Guinea and some of the nearby islands as 360-2300 m, which would imply that it can be happy under a wide range of temperatures.