Yes, Plumeria flowers can be pollinated at any time of day, as long as they are receptive and contain viable pollen. Most Plumeria species have flowers that remain open for an extended period, allowing pollinators to visit them throughout the day. However, pollination activity is often highest during the peak foraging hours of pollinators, which are typically during the warm, sunny hours of the day. Pollinators, especially bees, are more active during daylight when flowers are open and nectar is readily available.