Moon Phases December 2021
The full moon in December 2021 is on 19 December at 04:35 UTC — traditionally called the Cold Moon. The new moon falls on 4 December at 07:43 UTC. Times are UTC.
Why the December 2021 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 | Waning Crescent | 11% |
| 2 | Waning Crescent | 5% |
| 3 | New Moon | 1% |
| 4 | New Moon | 0% |
| 5 | New Moon | 2% |
| 6 | Waxing Crescent | 7% |
| 7 | Waxing Crescent | 15% |
| 8 | Waxing Crescent | 24% |
| 9 | First Quarter | 34% |
| 10 | First Quarter | 45% |
| 11 | First Quarter | 55% |
| 12 | First Quarter | 65% |
| 13 | Waxing Gibbous | 74% |
| 14 | Waxing Gibbous | 82% |
| 15 | Waxing Gibbous | 89% |
| 16 | Waxing Gibbous | 94% |
| 17 | Full Moon | 98% |
| 18 | Full Moon | 100% |
| 19 | Full Moon | 100% |
| 20 | Full Moon | 98% |
| 21 | Waning Gibbous | 95% |
| 22 | Waning Gibbous | 90% |
| 23 | Waning Gibbous | 83% |
| 24 | Waning Gibbous | 75% |
| 25 | Last Quarter | 66% |
| 26 | Last Quarter | 56% |
| 27 | Last Quarter | 46% |
| 28 | Last Quarter | 35% |
| 29 | Waning Crescent | 24% |
| 30 | Waning Crescent | 15% |
| 31 | Waning Crescent | 7% |
Illumination at noon (UTC) for each day.
Frequently asked questions
When is the full moon in December 2021?
The full moon in December 2021 is on 19 December at 04:35 UTC, traditionally called the Cold Moon.
What time is the full moon in December 2021?
The moon reaches full phase at 04:35 UTC on 19 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 2021 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 2021?
The new moon in December 2021 is on 4 December at 07:43 UTC.