Twelve peaks, in date order, each with the fraction of the Moon lit at the peak instant. 5 of the twelve fall under a Moon less than half lit — those are the nights worth keeping free.
"Usable" means the Moon is less than half lit at the peak instant. The filter is a checkbox and a CSS rule — no JavaScript, and no hidden scoring.
| Peak (UTC) | Shower | Weekday | Moon | ZHR | Radiant dec | Best from |
|---|---|---|---|---|---|---|
| Quadrantids | Monday | 12% waning crescent | 110 | +49.8° | North | |
| April Lyrids | Friday | 95% waning gibbous | 18 | +33.4° | North | |
| eta-Aquariids | Thursday | 0% new Moon | 50 | −0.5° | Both | |
| Southern delta-Aquariids | Saturday | 4% waning crescent | 25 | −16.1° | Both | |
| Perseids | Friday | 87% waxing gibbous | 100 | +57.9° | North | |
| October Draconids | Saturday | 67% first quarter | 5 | +55.9° | North | |
| Orionids | Friday | 58% last quarter | 20 | +15.7° | Both | |
| Southern Taurids | Saturday | 47% first quarter | 7 | +13.9° | Both | |
| Northern Taurids | Saturday | 98% full Moon | 5 | +22.8° | Both | |
| Leonids | Thursday | 80% waning gibbous | 12.5 | +21.8° | Both | |
| Geminids | Tuesday | 98% full Moon | 150 | +32.3° | North | |
| Ursids | Thursday | 21% waning crescent | 10 | +75.8° | North |
Peak instants are solved from each shower's tabulated solar longitude of maximum, referenced to the J2000 equinox, and are given in UTC — convert to your own clock before setting an alarm. The peak is an instant, not a night: the useful night is usually the one whose small hours contain it.
Strongest showers among those with a usable Moon. Rate matters, but a Moon you cannot escape matters more.
Peaks 4 January 2027 · active 28 December – 12 January
This year that means a dark sky — the Moon is close to new and takes almost nothing away.
Peaks 6 May 2027 · active 19 April – 27 May
This year that means a dark sky — the Moon is close to new and takes almost nothing away.
Peaks 31 July 2027 · active 12 July – 23 August
This year that means a dark sky — the Moon is close to new and takes almost nothing away.
One email seven days before a peak so you can keep the night free, and one on the evening itself with the verdict for your location. If your sky is going to be hopeless that night, the second email tells you the next good night instead of pretending otherwise.