YozoraAtlas

How dark is the sky in Vaud?

Sky darkness for 4 towns and parks in Vaud, worked out from NASA satellite images of light at night (2025). 3 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Gruyère Pays-d'Enhaut Regional Park (21.37, Bortle 4), the brightest Lausanne (19.60, Bortle 5). Milky Way season in Vaud runs May to July: on moonless nights the bright core stands clear of the horizon, climbing to about 15° at its highest.

19 Bortle class, 1 pristine to 9 city center park or dark-sky place city

Numbers like 21.95 or 16.97 are the brightness of the sky overhead on a clear, moonless night, in mag/arcsec². The scale runs backwards: a lower number means a brighter sky, from about 22 for a natural sky to about 17 in a city center.
How the readings are made

NASA satellite night-lights map of Vaud with every place marked

Darkest skies in Vaud

  1. Gruyère Pays-d'Enhaut Regional ParkBortle 421.37
  2. Yverdon-les-BainsBortle 420.56
  3. MontreuxBortle 420.54

Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.

Brightest city skies in Vaud

  1. LausanneBortle 519.60

All 4 places in Vaud

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Gruyère Pays-d'Enhaut Regional Park4Lausanne5Montreux4Yverdon-les-Bains4