YozoraAtlas

How dark is the sky in Leiria?

Sky darkness for 4 towns and parks in Leiria, 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 Serras de Aire e Candeeiros Natural Park (20.64, Bortle 4), the brightest Leiria (19.15, Bortle 6). Milky Way season in Leiria runs March to September: on moonless nights the bright core stands clear of the horizon, climbing to about 22° 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 Leiria with every place marked

Darkest skies in Leiria

  1. Serras de Aire e Candeeiros Natural ParkBortle 420.64

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 Leiria

  1. LeiriaBortle 619.15
  2. Marinha GrandeBortle 619.46
  3. Caldas da RainhaBortle 519.60

All 4 places in Leiria

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Caldas da Rainha5Leiria6Marinha Grande6Serras de Aire e Candeeiros Natural Park4