StarsOut
Should you go outside tonight?
Great night tonight
Clear skies and dark conditions. Go outside.
Graz
8.5
out of 10
Cautious estimate
Models split — score biased toward the cloudier forecast.
Peak 2h
9.700:00–02:00
Prime 21–01
9.321:00–01:00
Best this week
8.7Sat, Jul 18
Moon
Waxing Crescent
5% lit
Moon doesn’t interfere — perfect darkness
🔭 Moon up: 07:37–22:13
📍 SW · 55°
Full moon: Jul 29
Sun ↓ 20:49·Dark from 21:49·72% clouds
Alert me on good nightsSky quality tonight
Best: 00:00–02:00This week’s nights
Europe/ViennaHow the score works
60% weight
Cloud cover
Layer-weighted across the best 2-hour window of the night. Low clouds block everything, thin high cirrus still lets bright stars through.
40% weight
Moon darkness
A new moon boosts the score. A full moon near midnight washes out all but the brightest stars. We ease the penalty after midnight when the moon is setting.