I just realized the last couple of evenings, while the data (temperature, barometer, humidity) update with time overnight, the displayed iOS image does not seem to update.
For example, this evening at about 9:42 pm (EST), the image which shows on iOS has a faint aircraft contrail. The same image shows on my WU page where it now says the image is three hours old, last updated 11:12 GMT (were are +5 hours UTC).
This is not a terrible problem, Bloom Sky movies are dawn to dusk as advertised. I just used to glance at them for cloud cover at night for amateur astronomy use, but now I realize it was probably the same image all late evening, bummer.