The starry sky in December 2025
In December, the summer constellations Swan, Lyra and Eagle are no longer visible, even in the early evening. They have already set or are in the process of setting.
The star chart for 10 p.m. shows the splendor of the winter constellations: Orion, Taurus, Gemini and Auriga have already risen. Even Sirius, the brightest fixed star in the terrestrial sky, is already visible above the south-eastern horizon. However, the autumn constellations are still visible in the south and southwest. Below the autumnal quadrilateral (the large square made up of three stars of Pegasus and one star of Andromeda) you will find the extended constellations of Aquarius, Pisces and Whale, which consist only of faint stars. Eridanus, the constellation between Whale and Orion, is also only faintly visible. On a clear night, however, you can try to follow the course of the stars from east to west.
In the south-east, Jupiter forms a conspicuous triumvirate with the twin stars Castor and Pollux.
The moon phases in December 2025
The planets in December 2025
Mercury is very well visible in the morning at the beginning of December with the best observation days around December 7. From 6:30 a.m. Mercury can then be found above the southeastern horizon.
The Venus is no longer visible in the morning sky; it will be in superior conjunction with the Sun at the beginning of 2026.
Mars has also been unobservable since September and, like Venus, will be in conjunction with the Sun at the beginning of 2026.
Jupiter in Gemini will not reach its opposition position until January 10. Nevertheless, the largest planet in the solar system can be observed optimally in December. On December 7, the waning moon will pass by Jupiter.
Saturn in Aquarius now sets earlier and earlier in the first half of the night and is therefore an object in the evening sky. In the second half of the night on December 27, Saturn and the waning crescent moon are close together. Their angular separation is only about three degrees.
Even weeks after the oppositionist Uranus in Taurus for most of the night.
Neptune in the constellation of Pisces can be observed in the evening hours.
In modified form from: The starry sky in December 2025 - Association of Star Friends e.V.