Helena, MT Night Sky Brightness
Helena, MT's night sky, measured from orbit
Helena's sky measures urban here. Sky glow overhead most nights. Typically only planets, the Moon, and a handful of the brightest stars are visible. That's brighter than 87.1% 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 Helena is from a meaningfully darker sky
69 miles from Helena, straight-line, sits Belgrade, MT, the nearest city here with a darker sky than Helena's own urban band.
Belgrade, MT is itself still a measured city, not a designated dark-sky park, this only compares against the 3,206 places this dataset covers.
How Helena compares nationally
Helena, MT has a population of about 34,729, one of 3,206 US cities of 10,000 or more residents in this dataset. Helena's position, 2,778 of 3,206, darkest to brightest, comes from the sampling method the methodology guide sets out.