Picking your night
Two things decide a Mauna Kea night: clouds and the moon. The clouds are knowable about a week out. The moon you can plan a trip around.
Next 7 nights
- TonightSep 1065% clear sky · 49°F, feels 43°0%Fair
- FriSep 1166% clear sky · 48°F, feels 42°2%Fair
- SatSep 1291% clear sky · 49°F, feels 47°6%Good
- SunSep 1359% clear sky · 50°F12%Fair
- MonSep 1471% clear sky · 51°F19%Good
- TueSep 1571% clear sky · 52°F28%Good
- WedSep 1680% clear sky · 51°F37%Good
Sky cover is the NWS forecast averaged over the truly dark hours of each night, over the Visitor Station at 9,200 ft. Temperature is that night's average once it is properly dark, and what the wind does to it. The far end of the week thins out; a blank row means the forecast does not reach that far yet, not that the night is bad.
The darkest nights ahead
No cloud forecast reaches this far, and none needs to. This is the moon, which is settled centuries ahead. If you are choosing which night of a trip to drive up, choose from here first and check the clouds when you get closer.
| Night | Moon | Moonless dark |
|---|---|---|
| Saturday, October 10 | 1% | 9.8 hr |
| Friday, October 9 | 0% | 9.8 hr |
| Thursday, October 8 | 2% | 9.7 hr |
| Saturday, September 12 | 6% | 9.2 hr |
| Wednesday, October 7 | 6% | 9.2 hr |
Ranked by hours of astronomical dark with the moon below the horizon, across the next 30 nights. That is not the same as the lowest moon: a 30% crescent that sets early leaves more usable dark than a thin one that hangs about until dawn.
The moon calendar
Around the new moon the summit sky is at its absolute darkest, and the Milky Way core is the show. Around the full moon, the landscape glows and the faint stuff is gone; still a beautiful drive, just a different one.
- Next new moon: Oct 10, 2026. The darkest week of the month runs a few nights either side of it.
- Next full moon: Sep 26, 2026.
Tonight, hour by hour
Booked on a good night? Tour vs driving yourself, compared
Sky cover, temperature and wind: National Weather Service. Moon phases, twilight and dark hours computed by this site.