Rancho Cucamonga, CA — light pollution & stargazing
Rancho Cucamonga, California has a light-pollution rating of about Bortle 8 — a city sky (very poor — city glow) — measured from VIIRS 2024 satellite night-lights at 42 nW/cm²/sr at the town center. The sky is bright enough to read by. Only the Moon, the planets, and the few brightest stars and clusters are visible — the constellations lose most of their fainter stars. The nearest genuinely darker skies are around Claremont, CA (about 7 mi away, Bortle 7). Tonight's Moon phase, cloud cover, and aurora odds load live below, computed in your browser. This is a satellite upward-radiance proxy for planning, not a survey-grade sky-brightness measurement.
Stargazing in Rancho Cucamonga tonight
- Estimated Bortle class
- 8 of 9
- VIIRS radiance (town center)
- 42 nW/cm²/sr
- Naked-eye limiting mag.
- 4.1–4.5
- Milky Way
- not visible
City sky. A satellite upward-radiance proxy for planning — not a survey-grade sky-brightness reading.
What you can see from Rancho Cucamonga
The sky is bright enough to read by. Only the Moon, the planets, and the few brightest stars and clusters are visible — the constellations lose most of their fainter stars.
Darker skies within reach
The nearest town in each darker class — your ladder from Rancho Cucamonga's sky toward truly dark skies.
| Town | State | Bortle | Sky | Drive |
|---|---|---|---|---|
| Claremont | CA | 7 | Suburban / urban transition | 7 mi |
| Jurupa Valley | CA | 6 | Bright suburban sky | 9 mi |
| Crestline | CA | 5 | Suburban sky | 20 mi |
| Agoura Hills | CA | 4 | Rural / suburban transition | 68 mi |
Frequently asked questions
- Can you see the Milky Way from Rancho Cucamonga, CA?
- Not really. At about Bortle 8 the Milky Way is not visible from Rancho Cucamonga — the sky is too light-polluted. The nearest genuinely dark skies are around Claremont, CA, about 7 mi away.
- How dark is the sky in Rancho Cucamonga?
- Rancho Cucamonga rates a city sky — about Bortle 8, with a naked-eye limiting magnitude around 4.1–4.5. That comes from a VIIRS satellite night-lights reading of 42 nW/cm²/sr at the town center. It is a satellite proxy for planning, not a survey-grade measurement.
- Where is the nearest dark sky to Rancho Cucamonga?
- The nearest town with genuinely darker skies is Claremont, CA — about 7 mi away at roughly Bortle 7. See the "darker skies within reach" list on this page for more options.
- Can I see the aurora from Rancho Cucamonga tonight?
- It depends on tonight's space weather. The live panel on this page reads the current NOAA aurora forecast for your latitude, along with cloud cover and the Moon — most U.S. locations only see aurora during strong geomagnetic storms.
The darkness rating is measured from VIIRS satellite night-lights at the town center and is a proxy for planning, not a survey-grade sky-brightness measurement — and the darkest skies are usually a short drive out of any town. Tonight's Moon, cloud, and aurora figures are live third-party forecasts that can change. See the methodology for sources and limits.
More in California
See every town's darkness rating in California, learn to read the Bortle scale, or check tonight's Moon phase.