Milky Way Planner has pages for 6 dark sky places in Poland: 4 communities, 1 park and 1 preserve. Their Bortle classes run from 2 to 8. Each page has the Bortle class, the best months for the Milky Way and a free visibility calendar.
Park · Bortle 2
Community · Bortle 5
Community · Bortle 6
Preserve · Bortle 7
Community · Bortle 8
Community · Bortle 6