A frequently asked question every spring is, "when do apple blossoms open?" Apple blossoms are unlike dandelions that open in the morning and close in the evening.
The answer to when apple blossoms open is especially relevant for fire blight blossom blight management. On very hot days during bloom, bacterial growth is explosive. On such hot days, even newly opened flowers are susceptible to infection if bacteria is transported to the floral stigma.
Watching blossoms open in real time is too slow of a timeline so check out this time lapse video. Watch as puffy pink buds open from 10:28 AM to 5:14 PM. The answer is that blossoms open throughout the day!
I suggest watching the following video in full screen and using the highest video quality.