| # | City | Bortle (est.) | Brightness | 2 classes darker |
|---|---|---|---|---|
| 1 | Geneva | 7–8 | 255 | ~25 km NNW |
| 2 | Basel | 7–8 | 255 | ~25 km NNE |
| 3 | Zürich | 7–8 | 255 | ~25 km SSE |
| 4 | Lausanne | 7–8 | 253 | ~25 km WNW |
| 5 | Bern | 7–8 | 254 | ~25 km SSW |
| 6 | Luzern | 7–8 | 255 | ~25 km S |
| 7 | Biel/Bienne | 7–8 | 255 | ~25 km NW |
| 8 | Lugano | 7–8 | 243 | ~25 km WNW |
| 9 | Winterthur | 6–7 | 233 | ~25 km SE |
| 10 | Sankt Gallen | 6–7 | 210 | ~25 km SSW |
Brightness is the NASA VIIRS Black Marble 2016 value at the city centre on a 0–255 scale; 255 is saturated. Cities are ordered by estimated sky brightness, which also counts the light within 30 km.