TEMPO.CO, Jakarta - The long, dark nights in December are anything but woeful, with multiple astronomical phenomena gracing the sky. In just a few days, this year’s celestial events will showcase their radiant glow throughout the month. From early planet sightings and a luminous supermoon to what astronomers tout as 2025’s finest meteor shower, December is a parade of skyward marvels.
Drawing insights from National Geographic, Accuweather, and Astronomy, here are the top must-view cosmic sights you’d want to appreciate this month.
Astronomical Phenomena in December
1. Supermoon - December 4
Arriving as the year’s last full moon, the Cold Moon also qualifies as a supermoon whose light will be at its brightest just as it draws closest to Earth. During this brief alignment, its disk can appear up to 14 percent larger and nearly 30 percent brighter than at its farthest point, offering a striking send-off to 2025’s celestial calendar. Reaching full phase at 8:20 a.m. EST on December 4, it becomes especially captivating at dusk on December 5, when it rises along the eastern horizon, from 3:54 p.m. in New York to 4:22 p.m. in Los Angeles.
2. Greatest Elongation of Mercury - December 7
Often elusive in the Sun’s glare, Mercury is entering its prime morning showing for Northern Hemisphere observers, culminating on December 7 as it reaches its greatest elongation from the Sun. Rising about an hour before sunrise throughout the first week of December, Mercury becomes noticeably easier to spot, with Venus climbing in close pursuit. The swift planet will sit low on the eastern horizon while the bright star Spica gleams roughly 30 degrees above it, offering a rare and elegant pairing.
3. Gemini Meteor Shower - December 13–14
The Geminids return this December to reclaim their reputation as one of the night sky’s most radiant annual performances. The shower peaks between the night of December 13 and the early hours of December 14, when ideal dark-sky conditions could yield well over 100 meteors per hour.
With activity beginning as early as 10 p.m., the Geminids are unusually accessible, making them perfect for families and casual skywatchers eager for an early spectacle. And with the waning crescent moon not rising until around 2 a.m., observers will enjoy a generous window of pristine darkness to catch everything from golden streaks to the occasional fireball tearing across the sky.
4. Optimal Orion Nebula Sighting - December 15
The next night, on December 15, skywatchers have the ideal window to study the ethereal Orion Nebula, often deemed a star-forming cradle of dust that is both enchanting and intriguing. Though only its faintest shimmer is visible unaided, this vast cradle of newborn stars glows with delicate blue, pink, and green hues. With a telescope, however, its intricate veils of dust and gas come alive, forming a celestial spectacle that’s unmistakable beneath Orion’s iconic three-star belt.
5. Winter Solstice in the Northern Hemisphere - December 21
December 21 ushers in the winter solstice, delivering the Northern Hemisphere’s shortest day and a long night that aurora chasers won’t take for granted. Although nothing guarantees a repeat of November’s electrifying auroral outburst, the lingering strength of the solar maximum keeps the odds promising for another luminous display. As the Northern Hemisphere tilts farthest from the sun at 10:03 a.m. ET, winter officially begins, while the Southern Hemisphere simultaneously welcomes its longest day and the start of summer.
6. Ursid Meteor Shower - December 21-22
The Ursids close out the celestial calendar with a quieter flourish, peaking on the night of December 21-22. Though far more modest than the Geminids, the shower produces a modest handful of meteors and benefits from a near-new moon and the deep darkness of the winter solstice. These subtle streaks are best sought in the late-night hours before dawn, when the radiant near Ursa Minor climbs highest. As the last reliable meteor display for months, the Ursids provide a gentle finale to the year’s celestial roster before the Quadrantids spark briefly to life in early January.
As December draws to a close, the season’s astronomical phenomena leave the night sky humming with quiet brilliance, each spectacle adding its own note to an already luminous month. From supermoon to meteor showers and nebular vistas, these final displays remind us why December remains a favorite for skywatchers. And if you’re eager to continue your celestial pursuits, don’t miss our guide on where to see the northern lights in Ontario for your next breathtaking encounter.
Read: Full Moon in December 2025: When to See Cold Supermoon in the U.S.
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