How dark is the sky in Banning, CA?
Banning's sky measures dark sky here. Among the darkest skies of any US city in this dataset. The Milky Way should be visible overhead on clear, moonless nights. That's brighter than 1.2% of the 3,206 US cities in this dataset.
Worth remembering: this is satellite radiance, not a ground observation. A true Bortle rating needs a human eye at night, this is the closest large-scale substitute.
Banning is already about as dark as this dataset gets
Nothing in this dataset's 3,206 US cities measures a darker sky than Banning. That doesn't mean nowhere is darker, unincorporated land and wilderness aren't part of this dataset at all, only incorporated cities of 10,000 people or more.
Banning against the rest of the dataset
Banning, CA counts roughly 31,929 residents, among the 3,206 US cities this site tracks. Among all 3,206 cities here, Banning ranks 38 from darkest to brightest, 1 being the darkest measured.