YozoraAtlas

How dark is the sky in Faro?

Sky darkness for 6 towns and parks in Faro, worked out from NASA satellite images of light at night (2025). 1 of them has skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Ria Formosa Nature Park (20.57, Bortle 4), the brightest Portimão (19.02, Bortle 6). Milky Way season in Faro runs March to September: on moonless nights the bright core stands clear of the horizon, climbing to about 24° 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 Faro with every place marked

Darkest skies in Faro

  1. Ria Formosa Nature ParkBortle 420.57

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 Faro

  1. PortimãoBortle 619.02
  2. FaroBortle 619.04
  3. QuarteiraBortle 619.12
  4. LagosBortle 619.23
  5. LaranjeiroBortle 520.34

All 6 places in Faro

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Faro6Lagos6Laranjeiro5Portimão6Quarteira6Ria Formosa Nature Park4