The last full moon of 2025 occurs on December 5th and will be a supermoon, a phenomenon in which Lua reaches perigee close to the full phase. The satellite will appear up to 14% larger and 30% brighter than a regular full moon. The month still holds the Geminídeas meteor shower, considered the most intense of the year, peaking between December 14th and 15th.
Other events include the greatest western elongation of Mercúrio on December 8 and visible approaches to planets such as Saturno, Júpiter, and Vênus. Most phenomena can be observed with the naked eye in places with low light pollution.
- Best time for a supermoon: dusk on the 5th, when it appears on the eastern horizon
- Peak of Geminídeas: night of the 14th until the early hours of December 15th
- Ideal locations: rural areas or parks away from big cities
Supermoon marks the beginning of the month
The supermoon on December 5th will be the last of the year. The phenomenon happens when the full moon coincides with the passage through perigee, the closest point to Terra.
The optical effect known as the moon illusion reinforces the impression of a larger size when seen close to the horizon. Prédios or trees in the foreground intensify this perception.
Mercury in best morning position
On December 8, Mercúrio reaches greatest western elongation. The planet will be visible in the pre-dawn sky.
Just look at the eastern horizon about an hour before sunrise. Vênus will appear right above, making it easier to find.
Geminids promise extended show
The Geminídeas meteor shower peaks on the night of December 14th to 15th. Especialistas indicate up to 120 meteors per hour in ideal conditions.
Lua will be in a thin waning phase, with only 30% illumination until around 2 am. Isso guarantees dark skies most of the night. The meteors appear to come from the constellation Gêmeos. Yellowish Traços and fireballs are frequent features.
The rain remains active until December 20th, but the peak concentrates the greatest activity. Temperaturas casualties require appropriate clothing for long observations.
Other planetary alignments
Saturn remains visible in the early evening throughout the month. The planet appears in the constellation of Aquário.
Jupiter reaches opposition in December and dominates the night sky. The gas giant is visible all night. Vênus remains bright in the morning sky. Marte begins to gain prominence at the end of the month.
Practical observation tips
Choose locations with a clear horizon and little artificial light. Regiões interior or national parks offer better conditions. Não Special equipment is required for most events. Binóculos help in observing planets.
Favorable conditions in 2025
The absence of a full moon during the peak of Geminídeas improves visibility. Esse scenario occurs rarely.
The southern hemisphere has an advantage in observing the Geminídeas. The radiant is higher in the sky compared to the northern hemisphere.
Complementary phenomena
Summer solstice in the Southern Hemisphere occurs on December 21st. The longest day of the year marks the official start of the season. Ursa Maior appears high in the northern sky, making it easier to locate other constellations. Órion continues as a reference in the summer.