How to choose a night for stargazing
A regular weather app tells you “partly cloudy, low 4°”. For stargazing you need more: which clouds, at what hour, where the Moon is and whether your optics will fog up. Here is the checklist we use for the 0–10 night score.
1. Clouds — and which ones
Low clouds (below 2 km) block the sky completely. Mid-level clouds (2–6 km) are almost as bad. High clouds (above 6 km) are often thin cirrus: they dim faint objects but the Moon and planets shine through. Always look at the hourly forecast — a cloudy evening is often followed by a clear night.
2. Real darkness
The sky is fully dark only during astronomical night, when the Sun is more than 18° below the horizon. In summer at northern latitudes (for example in the Baltics) there may be no astronomical night at all for weeks — the sky stays blue-grey all night.
3. The Moon
A bright Moon is the biggest natural light polluter. For galaxies, nebulae and the Milky Way choose nights around the new Moon, or the hours after moonset. The Moon itself, planets and double stars are fine any time — the Moon is most interesting near first and last quarter.
4. Dew and wind
When the air cools to the dew point, lenses and mirrors fog up. Humidity above about 90% or a small gap between temperature and dew point means: bring a dew heater or shield. Gusts above 30–40 km/h shake a telescope — look for shelter behind trees or buildings.
5. How far ahead to trust the forecast
Cloud forecasts are good for about 24 hours and get less reliable after that. Plan with a 3-day forecast, then check again on the day — and an hour before you leave.
Do it in one minute
Type your town on the home page or tap a place on the sky map: the night score already combines clouds by layer, darkness, the Moon, dew, wind and light pollution, and shows the best hours to go out.