YozoraAtlas

How dark is the sky in Zagreb County?

Sky darkness for 2 towns and parks in Zagreb County, 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 Žumberak-Samobor Mountains Nature Park (21.29, Bortle 4), the brightest Velika Gorica (19.50, Bortle 6). Milky Way season in Zagreb County runs April 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 Zagreb County with every place marked

Darkest skies in Zagreb County

  1. Žumberak-Samobor Mountains Nature ParkBortle 421.29

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 Zagreb County

  1. Velika GoricaBortle 619.50

All 2 places in Zagreb County

Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Velika Gorica6Žumberak-Samobor Mountains Nature Park4