Geneva sits between the Jura mountains and the Alps, both of which offer rapid escapes from the city's Bortle 6 glow. The Jura to the north-west reaches Bortle 4 within 30–40 minutes, while the higher Alpine valleys and passes to the south-east deliver Bortle 3 skies with superb high-altitude transparency. The Lake Geneva basin can trap winter haze and fog, so observers head uphill for clear, dry air above the inversion layer. At 46.2°N, Geneva has classic northern skies, and the Alpine peaks make for spectacular dark-sky backdrops.