Ontario skywatchers will be treated to a spectacular celestial show next month as the Cold Moon—the final supermoon of 2025—rises in early December.
December’s full moon carries names rooted in Indigenous and early settler traditions, each describing the deepening winter season and the year’s longest nights. The Mohawk call it the Cold Moon, while the Mohican refer to it as the Long Night Moon. The Cree have several names tied to harsh winter conditions, including the Drift Clearing Moon, Frost Exploding Trees Moon and Hoar Frost Moon. Other names include the Western Abenaki’s Winter Maker Moon, the Dakota’s Moon When the Deer Shed Their Antlers, and the Anishinaabe’s Little Spirit Moon. In European tradition, it was called the Moon Before Yule, marking the approach of solstice celebrations.
According to The Old Farmer’s Almanac, the Cold Moon will reach peak illumination on Thursday, Dec. 4 at 6:14 p.m. EST. Although it will appear full throughout the night, the best viewing opportunities will be on Dec. 4 and 5 shortly after moonrise, when the moon may look larger and more colourful due to the well-known “moon illusion” effect.
This full moon also qualifies as a supermoon, occurring when the Moon is near perigee—its closest point to Earth. While the visual difference is subtle, supermoons can appear up to 8% larger and 16% brighter than usual. They can also generate slightly higher ocean tides known as “perigean spring tides” or “king tides.”
December’s lunar phases (Eastern Time) include:
- Full Moon: Dec. 4 at 6:14 p.m.
- Last Quarter: Dec. 11 at 3:52 p.m.
- New Moon: Dec. 19 at 8:43 p.m.
- First Quarter: Dec. 27 at 2:10 p.m.
The Old Farmer’s Almanac also outlines traditional best days for December activities aligned with the lunar cycle, including harvesting crops, setting eggs, and fishing—conditions expected to be most favourable between Dec. 1–4 and Dec. 19–31.
This Cold Moon marks the third and final supermoon of 2025, following October’s Harvest Supermoon and November’s Beaver Supermoon. For those who miss December’s display due to cloud cover, the next supermoon will arrive soon: Jan. 3, 2026, known as the Wolf Moon. Two more supermoons are expected later in 2026, on Nov. 24 and Dec. 24.