The 2025 Cold Moon rising low on the horizon, appearing unusually bright and large as December’s final supermoon (Photo: File)
The final full moon of 2025 promises a memorable show as the Cold Moon rises on 4 December. Already associated with ushering in the deepest chill of early winter, this full moon has an added thrill because it is also a supermoon.
Due to its closer than usual approach to Earth, combined with the natural illusion that makes it look bigger when near the horizon, the December Cold Moon promises a striking end to the year's lunar calendar.
Full illumination for the Cold Moon arrives at 6:14 p.m. EST on December 4. While the peak brightness is noteworthy, the most dramatic scenes will play out just after moonrise.
For instance, moonrise for New York occurs at 3:54 p.m. EST while Los Angeles sees it at 4:22 p.m. PST. In other parts of the world, observers can expect similarly impressive scenes just after the moon rises above the horizon.
The best viewpoints are locations with an unobstructed view of the eastern horizon. Shorelines, rural fields, high terraces and hilltops afford the clearest lines of sight. City observers will probably want to head to parks or rooftops where buildings won't obstruct the first moments of moonrise, which often prove the most photogenic.
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The full moon known as the Cold Moon appears annually, but it does not always come as a supermoon. The last such Cold Moon occurred in 2023 when an unusual alignment brought a run of successive full moons relatively close to Earth. That occasion saw similar excitement by skywatchers around the world.
The next notable Cold Moon supermoon will come in 2028, when the lunar cycle again aligns with perigee in early December. The full moon appears monthly, but the supermoons are more intermittent, depending entirely on the moon's orbital position.
A supermoon usually occurs when the Moon is at or near perigee-the point in the orbit closest to the Earth-when it reaches full phase. This month, the Moon will sit about 357,218 kilometres away from Earth, making it larger and brighter compared with a normal full moon.
While modest, that change in distance can still make the lunar disk seem as much as 14 percent larger and 30 percent brighter.
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The famous moon illusion plays a big role. When the moon is low, surrounding elements like trees, buildings, and distant hills create visual cues that make the brain interpret the moon as larger than it truly is. With the moon already closer to Earth this month, that illusion becomes even more convincing.
The Cold Moon completes a super year that included three supermoons and two total lunar eclipses. Among the highlights of 2025 were the blood moons of March and September.
The next act in this lunar drama opens on 3 January 2026 with the Wolf Moon, which will be the fourth consecutive supermoon in this unusual succession.
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Disclaimer: This article is for general astronomy information only. Viewing conditions may vary by location and weather. Always follow local safety guidelines outdoors.
