‘Cold Moon’ and final supermoon of 2025 to shine over Ontario skies next month

The final supermoon of 2025 is set to shine over Ontario skies next month!

December’s full moon is known as the Cold Moon, a name rooted in Indigenous and early settler traditions that mark the arrival of deeper winter and the longest nights of the year.

The Mohawk use the name Cold Moon, while the Mohican call it the Long Night Moon because it rises during the longest nights of the year. The Cree refer to it as the Drift Clearing Moon, Frost Exploding Trees Moon or Hoar Frost Moon, each pointing to winter conditions. The Western Abenaki name is Winter Maker Moon, the Dakota call it the Moon When the Deer Shed Their Antlers, and the Anishinaabe refer to it as the Little Spirit Moon. In Europe, it was known as 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. While the Moon will appear full throughout the evening, the best viewing will be on the nights of Dec. 4 and Dec. 5 shortly after moonrise. At that time, the Moon may appear larger and more colourful due to the moon illusion, a visual effect that occurs when it sits low on the horizon.

A supermoon happens when the Moon is near perigee, its closest point to Earth. This can make it appear up to eight per cent larger and 16 per cent brighter, though the difference is subtle. Supermoons can also cause slightly higher ocean tides due to the Moon’s stronger gravitational pull, a phenomenon sometimes referred to as “perigean spring tides” or “king tides.”

Here’s a look at December’s lunar schedule (Eastern Time):

• 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 highlights the best days in December for traditional activities tied to the Moon’s cycle:

• Aboveground crops are best harvested Dec. 25 and 26.
• Belowground crops should be harvested Dec. 6 and 7.
• The best days for setting eggs are Dec. 4–5, 12–13 and 31.
• Fishing conditions are most favourable from Dec. 1 to 4 and Dec. 19 to 31.

This Cold Moon marks the third and final supermoon of 2025, following October’s Harvest Supermoon and November’s Beaver Supermoon. If clouds interfere with viewing next month, skywatchers won’t have to wait long for another chance as the next supermoon will arrive on Jan. 3, 2026, known as the Wolf Moon. Two additional supermoons are expected later in 2026, on Nov. 24 and another on Dec. 24.