How dark is the sky in Oakley, CA?
Oakley reads as suburban edge on this dataset's scale. A noticeable glow near the horizon. Brighter stars and constellations are easy to pick out; the Milky Way is washed out. That's brighter than 24.2% 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.
How far Oakley is from a meaningfully darker sky
Rio Vista, CA, about 12 miles away as the crow flies, measures in the rural band, one step darker than Oakley. Actual driving distance will run longer than that straight-line figure.
Rio Vista, CA is itself still a measured city, not a designated dark-sky park, this only compares against the 3,206 places this dataset covers.
Oakley against the rest of the dataset
Oakley, CA has a population of about 47,158, one of 3,206 US cities of 10,000 or more residents in this dataset. Among all 3,206 cities here, Oakley ranks 771 from darkest to brightest, 1 being the darkest measured.