How Tonight Score Is Weighted
The Tonight score is weather-first. It is not a moon score, Bortle score, or lab instrument reading.
Tonight Observing Score · Is Tonight Good for Stargazing?
Inputs (approximate contribution)
| Input | Role | |-------|------| | Cloud cover | Largest share. Clearer sky raises the score. | | Dew risk | Low / moderate / high humidity stress on optics and transparency feel. | | Transparency | Aerosol optical depth when available (haze). | | Astronomical dark hours | Rewards real dark time, not just evening twilight. | | Nearby clear window | Small bonus when a usable clear stretch is soon. | | Rain risk | Penalty when precip probability is high in dark hours. |
Bands: 70+ Go, 45-69 Maybe, under 45 Skip.
What it does not score
- Light pollution / Bortle (use Dark Sky Finder).
- Moon phase washout alone (use Dark Sky Window).
- Target altitude for galaxies or planets (use planners for those objects).
Sky Events may show a different “tonight” style score that mixes Moon and sky quality. Stargazing Weather and Tonight Score stay weather-first on purpose.
How to use the number
Treat it as a go/no-go for driving. Always open hourly weather for timing. Two pins a short drive apart can differ when showers or coastal haze sit on one side of town.