Philadelphia sits in the densely lit Northeast Corridor, with Bortle 8–9 skies across the city, but the Pocono Mountains to the north and the Pine Barrens of New Jersey to the east-south-east both offer darker Bortle 4 skies within 90 minutes. Cherry Springs State Park — the East Coast's darkest site at Bortle 2 — is a longer drive into northern Pennsylvania. The Mid-Atlantic's humid summers bring haze, but crisp autumn and winter high-pressure nights offer good transparency. At 40°N, the city has classic northern-hemisphere skies.