Glendora, CA: how dark is the sky here?

Glendora 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 22.6% of the 3,206 US cities in this dataset.

This comes from a satellite measuring light radiating upward, not a person's eyes on the ground, so it isn't the same as a Bortle class, though the two track each other closely.

The nearest darker sky to Glendora

The closest place in this dataset with a meaningfully darker sky is Duarte, CA, roughly 6 miles away in a straight line, rated rural. Road distance will be more.

Duarte, CA is itself still a measured city, not a designated dark-sky park, this only compares against the 3,206 places this dataset covers.

How Glendora compares nationally

Glendora, CA has a population of about 50,101, one of 3,206 US cities of 10,000 or more residents in this dataset. Glendora places 721 of 3,206 cities in this dataset's darkest-to-brightest order.