🌌 Tonight on Mauna Kea — a 100/100 night above the clouds

At 4,200 m, you're already above most of the atmosphere's mischief — and tonight the summit delivers its best: Bortle 2 darkness, rock-steady 16 km transparency, and a viewing-quality score of 100. Best of all, the Moon is a razor-thin waning crescent (~3% illuminated) sitting below the horizon all night — zero lunar interference for deep-sky work.

⏱ Hour-by-hour evolution

• 20:00–21:00 — The "softest" hours: cloud cover peaks near 29% with a lingering moisture signal, but every hour still flags as good. Temps near 13°C.
• 22:00–23:00 — The sky rinses out beautifully: clouds drop to 18%, then hit the night's minimum of 12% at 23:00. This is your transparency sweet spot.
• 00:00–01:00 — The moisture reading drops to zero and winds ease to their calmest of the night (~2.5 m/s). Temperature has glided down to ~11.4°C — a steady cooling trend of about 1.6°C from dusk to dawn, so layer up.

🔭 What to chase

• Venus (−4.23) — the evening blaze. It transited at 15:17, so catch it low in the west early in your session before it sinks into the haze.
• Saturn (0.57) — the payoff object. It culminates at 03:57, riding high for crisp ring detail after midnight.

Deep-sky lineup: The summer globulars dominate — M13 in Hercules, M22 and M4 toward the Scorpius-Sagittarius core, plus the glittering open clusters M7 and M6. As the night matures, swing northeast for M31 (Andromeda) and M33 — with a moonless Bortle 2 sky, M33 becomes a naked-eye whisper.

The golden window: 23:00–00:00 — minimum clouds, moisture gone, and Saturn climbing into prime position. Clear skies! 🔭✨