Full Moon field guide · UK dates
The Worm Moon
A spring-thaw name linked in popular accounts with softened ground and the return of visible invertebrate activity.
What Worm Moon means
Worm Moon is the familiar March label. Its exact story varies: modern accounts refer to earthworm casts or other signs appearing as frozen ground thaws, while older regional calendars use several different spring names.
The date sits close to the seasonal turn, so its path and rise time can change noticeably from year to year.
Next UK occurrence
Mon, 22 Mar 2027
Exact full Moon: . Brown lunation 1289.
Three-year almanac
Worm Moon dates, 2026–2028
| Year | UK date and time | Lunation | Calendar |
|---|---|---|---|
| 2026 | 1276 | Open month | |
| 2027 | 1289 | Open month | |
| 2028 | 1301 | Open month |
02
What to notice from the UK
Use binoculars along the terminator on the nights before full Moon, when low shadows reveal more surface relief.
The disc looks full on the nights around the exact instant. A low Moon may look larger or warmer because of perspective and the atmosphere, not because its phase changed.
03
Other recorded labels
Almanacs do not share one universal naming system. This month is also listed as Rethe Moon in an Old English grouping and Moon of Winds in a modern Celtic-revival grouping.