Rancho Cucamonga, CA: how dark is the sky here?

Satellite radiance puts Rancho Cucamonga in the suburban band. Light dome dominates much of the sky. Only the brightest stars and planets stand out clearly. That's brighter than 51.1% 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.

How far Rancho Cucamonga is from a meaningfully darker sky

Upland, CA, about 5 miles away as the crow flies, measures in the suburban edge band, one step darker than Rancho Cucamonga. Actual driving distance will run longer than that straight-line figure.

Upland, 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 Rancho Cucamonga compares nationally

Rancho Cucamonga, CA counts roughly 176,675 residents, among the 3,206 US cities this site tracks. Rancho Cucamonga places 1,629 of 3,206 cities in this dataset's darkest-to-brightest order.