SeaTac, WA Night Sky Brightness
How dark is the sky in SeaTac, WA?
SeaTac 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 99.9% 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, covered fully in the Bortle scale guide.
The nearest darker sky to SeaTac
3 miles from SeaTac, straight-line, sits Tukwila, WA, the nearest city here with a darker sky than SeaTac's own inner-city band.
Tukwila, WA is itself still a measured city, not a designated dark-sky park, this only compares against the 3,206 places this dataset covers.
SeaTac against the rest of the dataset
About 34,024 people live in SeaTac, WA, sized enough to appear in this dataset of 3,206 incorporated US cities. Ranked against the other 3,206 cities here by the methodology guide's own sampling, SeaTac comes in at 3,184, darkest to brightest.