Yuma's reading looks wrong, and this site says so rather than hide it
Yuma's satellite reading came back at exactly zero, which is not a real measurement for a city of 103,559 people, it means the sample point most likely missed the lit part of town, landing on open water, a shadowed hillside, or just a bad coordinate. Real cities this size do not read true zero.
This is flagged instead of shown as a normal result because reporting it as "Yuma's dark sky" would be reporting a data error as a fact, see the data quality guide for how this gets checked.
The nearest reliable reading to Yuma
Somerton, AZ is about 12 miles from Yuma and has a trustworthy reading: rural band. It's the closest usable stand-in until Yuma's own figure is corrected.
Because Yuma's own coordinate is what produced the bad reading, that distance figure is itself approximate, not a confirmed measurement.
Yuma against the rest of the dataset
Yuma, AZ has a population of about 103,559, one of 3,206 US cities in this dataset, 3,187 of which have a usable brightness reading today.