December 1, 2025: Three bright planets highlight December’s sky as Mercury reaches its best morning appearance, Jupiter approaches opposition, and the moon moves through its phases.
by Jeffrey L. Hunt
December 2025 Sky Watching
As December ends the calendar year, three bright planets are visible as Venus and Mars move toward conjunctions with the sun.
Sun: At Chicago’s latitude, daylight is 9 hours, 22 minutes. By the solstice, the first day of astronomical winter on the 21st, daylight shrinks 14 minutes from today. In comparison, in Miami, today’s daylight spans 10 hours, 38 minutes and is reduced by only six minutes at the solstice. Farther northward in Anchorage, daylight lasts 6 hours, 5 minutes and shrinks 38 minutes on winter’s first day.
The earliest sunset occurs December 3–14, while the latest sunrise occurs December 28–January 10.
Moon: This month’s phases – Full, Dec. 4; Last Quarter, Dec. 11; New, Dec. 19; First Quarter, Dec. 27. For those hoping for a bright Christmas moon, its phase is a thick waxing crescent, 30% illuminated. The lunar orb occults (eclipses) the Pleiades star cluster on the night of December 3–4 and Regulus on the 9th for sky watchers in Canada and Greenland. It is near Spica on the 14th. During the next lunation, it is near the Pleiades on the evenings of the 30th and 31st.
Inner Planets
Mercury: The speedy planet is in the midst of its best morning apparition of the year. This morning it rises 99 minutes before the sun. When it reaches greatest elongation on the 7th, Mercury rises nearly 10 minutes earlier than this morning. At 45 minutes before sunrise, find it less than 10° above the east-southeast horizon below the Scorpion’s claws – Zubenelgenubi and Zubeneschamali. As Mercury retreats back into morning twilight, it passes Scorpius’ brighter stars.
Use a binocular to see the crescent moon to Mercury’s upper right on the 17th. By the solstice, it is only 5° above the east-southeast horizon, but easily visible with a clear sightline.
Venus: The Morning Star disappears into bright morning twilight as it reaches superior conjunction on the far side of the sun on January 6th. It reappears as the Evening Star during late March.
Outer Planets
Mars: The Red Planet continues its slide toward solar conjunction on January 9th. It slowly moves into the eastern morning sky. Its visibility suffers from a shallow angle the plane of the solar system (ecliptic) makes with the eastern horizon. This delays the planet’s return to a darker sky before sunrise. Mars and the moon appear in the eastern sky in the same binocular field of view on June 12th.
Jupiter: With Venus hidden in bright sunlight, Jupiter is the brightest starlike body. Approaching opposition on January 10th, it rises at sunset in the east-northeast. It retrogrades in front of Gemini near Pollux – one of the Twins. It passes Pollux for the second in a series of three conjunctions on December 13th. The bright moon is near Jupiter on the morning of the 7th and evenings of December 6th and 7th.
Saturn: The Ringed Wonder begins the month in the southeastern sky after sunset. It slowly moves eastward in front of Pisces after its retrograde ended late last month. It is in a prime location to see its rings from the edge, occurring once every 15 years, that appear as a line through the planet. Saturn is dimmer than average because the rings reflect light away from Earth, resulting in a slightly dimmer planet. By month’s end, the planet is about halfway from the southern horizon to overhead as darkness falls. The evening crescent moon is nearby on the 26th.
Uranus: The Tilted World retrogrades in front of Taurus near the Pleiades star cluster, resembling a tiny dipper. Several days after its opposition, the planet is low in the east after sunset. On moonless nights, the planet is visible to the unaided eye from rural areas. From suburban areas, use a binocular when the moon is at the crescent phases.
Neptune: The solar system’s most distant planet is in the same binocular field with Saturn, best viewed on moonless nights when in the southern sky. Neptune is considerably dimmer than 20, 24, 27, and 29 Piscium (Psc), which are in the field of view. Use averted (peripheral) vision to see it.
Meteor Showers and Stars
Meteor Showers: The Geminid meteor shower peaks before the onset of morning twilight on the 14th. The point in the sky where the shower emerges is near Castor. While the meteors can be seen anywhere in the sky, most can be seen by looking toward Gemini. With the year’s highest rate, expect to see about 20 meteors per hour, less in regions with more outdoor lighting. (For Castor’s location, see the Jupiter chart.)
Stars: The winter stars, which are visible in the south after sunset during winter’s midpoint, are entering the eastern sky during the early evening. Aldebaran rises at sunset on December 6th. Orion enters during the New Year with Betelgeuse rising at sunset on January 1st.
Dress warmly and step outside to look at the night sky. On moonless nights look for Uranus and Neptune through a binocular.
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