Seattle, WA Night Sky Brightness
Seattle, WA's night sky, measured from orbit
Seattle reads as inner-city on this dataset's scale. Among the brightest skies in this dataset. Usually just the Moon and a few of the brightest stars or planets cut through. That's brighter than 98.8% of the 3,206 US cities in this dataset.
Note the source: a satellite reading of upward light, not a visual Bortle scale reading. The two measure related but different things, explained in the Bortle scale guide.
How far Seattle is from a meaningfully darker sky
Mercer Island, WA, about 7 miles away as the crow flies, measures in the rural band, one step darker than Seattle. Actual driving distance will run longer than that straight-line figure.
Mercer Island, WA is itself still a measured city, not a designated dark-sky park, this only compares against the 3,206 places this dataset covers.
How Seattle compares nationally
Seattle, WA has a population of about 780,995, one of 3,206 US cities of 10,000 or more residents in this dataset. Seattle's position, 3,150 of 3,206, darkest to brightest, comes from the sampling method the methodology guide sets out.