Lua is in the waning phase this Thursday, December 18, 2025. Essa stage of the lunar cycle only has around 3% illumination, making the satellite difficult to observe with the naked eye during most of the night. The illuminated portion progressively decreases, approaching the new Lua, which will occur the following day. Observadores in Brasil may notice a thin slice of light in the hours before dawn.
The December 2025 lunar cycle began with full Lua on day 4, followed by waning on day 11. Essa sequence follows the pattern of approximately 29.5 days for a complete cycle. The current phase reflects the gradual alignment of Lua with Sol, reducing visible sunlight reflection from Terra.
- Full moon: December 4th
- Last Quarter: December 11th
- New Moon: December 19
- First Quarter: December 27th
These dates correspond to the exact moments of transition, with minimal variations depending on geographic location.
Main phases of the month
The full Lua of December occurred at the beginning of the month, providing brighter nights. Essa phase marks the point of greatest visibility of the satellite, when the lunar disk appears fully illuminated. Then the transition to waning reduces the visible area day by day.
The current waning phase sets the stage for the renewal of the cycle. Observadores Nocturnal people notice less brightness in the sky, favoring the view of stars in places with little light pollution.
Characteristics of the waning
In the waning phase, the illumination of Lua gradually decreases until it almost disappears. On December 18, visibility is limited to a small portion, visible mainly in the early morning hours. Essa configuration results from the positioning of Lua in relation to Terra and Sol.
The natural satellite influences phenomena such as ocean tides due to its gravitational force. However, there is no scientific evidence of direct impacts on human aspects, such as mood or health.
Observation in the southern hemisphere
At Brasil, the waning Lua appears with the left-lit part of the sky. Essa orientation differs from the northern hemisphere, where the opposite occurs. The average distance from Lua to Terra is about 384 thousand kilometers, varying due to the elliptical orbit.
Observing the sky at this stage requires ideal conditions, such as the absence of clouds and urban lights. Binóculos or simple telescopes reveal details of the lunar surface even in low light.
Complete lunar cycle
The lunar cycle lasts an average of 29.5 days and is divided into four main phases. Cada one of them corresponds to different alignments between Terra, Lua and Sol. The new Lua marks the beginning, when the satellite becomes invisible as it is aligned between Terra and Sol.
The crescent increases the illumination, followed by the flood, with the disc fully visible. The waning one, like the current one, closes the cycle by reducing the reflected light.
Influence on tides
Lunar gravity directly affects the oceans, causing variations in tides. Durante syzygy phases, such as new and full, the tides are more intense. In the waning and waxing periods, the variations tend to be smaller.
These phenomena occur across the planet, with local differences due to coastal geography. Instituições like Inmet monitor astronomical data for accurate predictions.
Observation Tips
To see the waning Lua on December 18, look east in the hours before sunrise. Locais elevated areas and away from cities offer better conditions. Aplicativos astronomy help to locate the satellite accurately.
The current phase is ideal for long exposure photography of the starry sky. The low lunar luminosity reduces interference in night images.
Detailed calendar
December 2025 features clear transitions in lunar phases. The new Lua on the 19th restarts the cycle, making the satellite invisible at night. Then, the crescent begins to increase in lighting until the end of the month.
These changes are predictable and are based on precise astronomical calculations. Calendários lunar aids in planning outdoor activities.
Astronomical aspects
The elliptical orbit of Lua causes variations in the distance to Terra, known as perigee and apogee. At perigee, the satellite appears larger and brighter. Superluas occur when the flood coincides with this proximity.
In 2025, December includes a supermoon at the beginning of the month. Observações professionals use telescopes to study lunar craters and seas.
Global visibility
The waning phase of December 18 is observable across the planet, with local times varying. In the southern hemisphere, the appearance differs slightly from that seen in the north. Lua remains the only natural satellite of Terra, with a diameter of about a quarter of the planet.
Space research continues to explore its composition and origin. Missões recent collect samples for scientific analysis.
Upcoming transitions
The new Lua arrives on December 19th, marking the end of the current cycle. Nesse moment, the satellite is positioned between Terra and Sol, becoming invisible. The transition begins a new period of luminous growth.
Observers await the crescent towards nights with more natural light. The lunar calendar serves as a reference for different cultures.
Related phenomena
Meteor showers and other celestial events gain prominence in phases of low lunar luminosity. In December, conditions favor observations on specific dates. Astrônomos amateurs take the opportunity to record the sky.
The gravitational influence of Lua extends to oceanographic and environmental studies. Accurate Dados assists in forecasting high and low tides.
