Clear skies over San Marcos, CA tonight

San Marcos ranks 280th out of 500 US cities for night-sky darkness, with a darkness index of 67 out of 100. That estimate comes from the population of every community within 150 km, weighted by distance — so what matters is the glow of the whole metro area, not just the city's own size.

That is middling — the brighter constellations and planets come through, but the Milky Way stays faint from inside town. A 30–60 minute drive away from the glow changes what you can see dramatically.

If you are willing to drive, Indio, CA sits under noticeably darker sky and is the nearest city on our ranking with a real improvement. Give your eyes about 20 minutes to adapt once you arrive, and avoid looking at your phone.

Light pollution is the part that does not change night to night. Cloud cover and moonlight do, which is what the forecast above tracks.