Moon Phases December 2025
The full moon in December 2025 is on 4 December at 23:14 UTC — traditionally called the Cold Moon. The new moon falls on 20 December at 01:43 UTC. Times are UTC.
Why the December 2025 full moon is called the Cold Moon
Named for the onset of winter cold.
These are the traditional Colonial and Native American names popularised by the farmers’ almanacs. They are folklore, not astronomy — the phase dates and times on this page are computed and verifiable, the names are naming convention.
Moon phase day by day
| Day | Phase | Illumination |
|---|---|---|
| 1 | Waxing Gibbous | 83% |
| 2 | Waxing Gibbous | 91% |
| 3 | Full Moon | 97% |
| 4 | Full Moon | 99% |
| 5 | Full Moon | 99% |
| 6 | Waning Gibbous | 96% |
| 7 | Waning Gibbous | 90% |
| 8 | Waning Gibbous | 83% |
| 9 | Waning Gibbous | 74% |
| 10 | Last Quarter | 64% |
| 11 | Last Quarter | 53% |
| 12 | Last Quarter | 43% |
| 13 | Last Quarter | 34% |
| 14 | Waning Crescent | 25% |
| 15 | Waning Crescent | 18% |
| 16 | Waning Crescent | 11% |
| 17 | Waning Crescent | 6% |
| 18 | New Moon | 2% |
| 19 | New Moon | 0% |
| 20 | New Moon | 0% |
| 21 | New Moon | 2% |
| 22 | Waxing Crescent | 6% |
| 23 | Waxing Crescent | 11% |
| 24 | Waxing Crescent | 18% |
| 25 | Waxing Crescent | 27% |
| 26 | First Quarter | 37% |
| 27 | First Quarter | 47% |
| 28 | First Quarter | 58% |
| 29 | First Quarter | 69% |
| 30 | Waxing Gibbous | 79% |
| 31 | Waxing Gibbous | 88% |
Illumination at noon (UTC) for each day.
Frequently asked questions
When is the full moon in December 2025?
The full moon in December 2025 is on 4 December at 23:14 UTC, traditionally called the Cold Moon.
What time is the full moon in December 2025?
The moon reaches full phase at 23:14 UTC on 4 December. It looks full to the naked eye for about a day either side of that instant, so the nights before and after are both worth watching.
Why is the December 2025 full moon called the Cold Moon?
Named for the onset of winter cold. These names come from Colonial and Native American tradition and were popularised by the farmers' almanacs — they are naming convention rather than astronomy, while the phase dates and times on this page are computed and verifiable.
When is the new moon in December 2025?
The new moon in December 2025 is on 20 December at 01:43 UTC.