Will tonight's sky be worth it?
Search a place to see whether tonight is worth the trip. The score blends cloud cover, moonlight, darkness and the length of the dark window.
Treat the score as odds, not a promise. Clouds do what they like.
Search a place or use your location to load tonight’s score.
Best national parks for stargazing
The table starts with parks and NPS units where certification details are verified. You can expand it to include extra candidate units marked as estimates.
| # | Park | State | Certified | Bortle | Clear nights | Score |
|---|
How the score works
No black box. For your location we read tonight's cloud cover, the moon's brightness, how dark your spot is and how many truly dark hours you get, then weigh them into a single number you can trust.
- Clouds carry the most weight, so a clear night beats everything else. We look at the forecast for the dark hours specifically, not whatever it happens to be doing right now, which is why a clear evening still scores well after sunset.
- Your viewing-spot picker sets how much light pollution sits over the exact place you will stand. A city centre washes out all but the brightest stars, while a dark-sky site shows thousands more.
- The moon's brightness comes from its phase, worked out right in your browser with no lookup. A bright moon costs you points, and we ease off when the moon has already dropped below the horizon.
- The dark window is how long the sky stays genuinely dark after twilight. When you are online we pull tonight's exact twilight times, otherwise we estimate them from your latitude and the date. Near midsummer at far-north latitudes the sky may never fully darken, and we say so plainly rather than show a misleading number.
How parks are ranked
Each park's rank blends how dark the site is with how often its nights run clear. Both feed a single 0 to 100 score, so the order is fully reproducible.
- Certification year and tier are verified against DarkSky International's registry and the National Park Service.
- Where those bodies do not publish a number for a specific unit, the darkness rating and the share of clear nights are our own estimates, drawn from the park's tier, how remote it is and its regional climate. Those figures are marked (est.) in the table so you always know which numbers are measured and which are reasoned.
- Download the CSV to see every value, including which ones are estimated.
Sources. DarkSky International certified-places registry, NPS Night Skies program, Open-Meteo for the forecast, sunrise-sunset.org for twilight times, and Sky & Telescope for the Bortle dark-sky scale.
A forecast of a chaotic sky is odds, not a promise. Always check a current local forecast before you drive out.