San Diego, December 2, 2025
San Diego residents can anticipate the final supermoon of 2025, which will brighten the sky on December 4. This event marks the third consecutive supermoon this year, following similar phenomena in October and November. The peak illumination will occur at 3:15 p.m. PST, with the best viewing opportunities during moonrise on December 5. Locals are encouraged to explore elevated and open areas for optimal viewing experiences.
San Diego to Witness Final Supermoon of 2025 on December 4
San Diego residents can look forward to the last supermoon of the year, set to illuminate the night sky on Thursday, December 4, 2025. This celestial event marks the third consecutive supermoon in 2025, following those in October and November.
What Is a Supermoon?
A supermoon occurs when a full moon coincides with its closest approach to Earth, known as perigee. During this time, the moon appears up to 14% larger and 30% brighter than when it’s at its farthest point from Earth, known as apogee. This phenomenon is a result of the moon’s elliptical orbit around our planet.
Optimal Viewing Times in San Diego
In San Diego, the full moon will reach its peak illumination at 3:15 p.m. PST on December 4. However, the most striking views will be during moonrise on Friday, December 5, when the moon ascends the eastern horizon approximately 25 minutes after sunset. This timing enhances the “moon illusion,” making the moon appear larger and more dramatic as it rises. For precise moonrise times, residents can consult local astronomical resources or use online moonrise calculators.
Best Locations for Viewing
To fully appreciate the supermoon, consider observing it from locations with an unobstructed view of the eastern horizon. Ideal spots include elevated areas, open fields, or east-facing coastlines. Such settings provide clear sightlines and minimize light pollution, offering optimal viewing conditions.
Understanding the ‘Cold Moon’
The December full moon is traditionally known as the “Cold Moon,” a name reflecting the chilly temperatures and long nights characteristic of this time of year in the Northern Hemisphere. This moniker has been used by various cultures to signify the onset of winter.
Additional Astronomical Events in December
Beyond the supermoon, December offers several other noteworthy celestial events:
- Geminid Meteor Shower (December 13–14): One of the most prolific meteor showers, the Geminids can produce up to 120 meteors per hour at their peak. The waning crescent moon will set early, providing dark skies ideal for meteor viewing.
- Mercury’s Greatest Elongation (December 7): Mercury will reach its greatest separation from the sun, making it visible in the pre-dawn sky. Observers can catch a glimpse of the “swift planet” about an hour before sunrise.
- Winter Solstice (December 21): Marking the shortest day and longest night of the year in the Northern Hemisphere, the winter solstice offers extended hours for stargazing.
For those interested in exploring these events further, local astronomy clubs and observatories often host public viewing sessions and educational programs throughout the month.
Key Features of the December 2025 Supermoon
| Feature | Details |
|---|---|
| Event | Last Supermoon of 2025 |
| Date | December 4, 2025 |
| Peak Illumination | 3:15 p.m. PST |
| Optimal Viewing Time | Moonrise on December 5, approximately 25 minutes after sunset |
| Best Viewing Locations | Elevated areas, open fields, east-facing coastlines with an unobstructed view of the eastern horizon |
| Traditional Name | Cold Moon |
| Additional Events in December | Geminid Meteor Shower (December 13–14), Mercury’s Greatest Elongation (December 7), Winter Solstice (December 21) |
FAQ
When is the last supermoon of 2025 in San Diego?
The last supermoon of 2025 will occur on Thursday, December 4, 2025, with peak illumination at 3:15 p.m. PST. The most striking views will be during moonrise on Friday, December 5, approximately 25 minutes after sunset.
What is a supermoon?
A supermoon occurs when a full moon coincides with its closest approach to Earth, known as perigee. During this time, the moon appears up to 14% larger and 30% brighter than when it’s at its farthest point from Earth, known as apogee.
Where is the best place to view the supermoon in San Diego?
Ideal viewing locations include elevated areas, open fields, or east-facing coastlines with an unobstructed view of the eastern horizon. Such settings provide clear sightlines and minimize light pollution, offering optimal viewing conditions.
What is the ‘Cold Moon’?
The December full moon is traditionally known as the ‘Cold Moon,’ a name reflecting the chilly temperatures and long nights characteristic of this time of year in the Northern Hemisphere. This moniker has been used by various cultures to signify the onset of winter.
What other astronomical events are happening in December?
December features several notable celestial events, including the Geminid Meteor Shower (December 13–14), Mercury’s Greatest Elongation (December 7), and the Winter Solstice (December 21). These events offer additional opportunities for stargazing and astronomical observation.
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Author: STAFF HERE SAN DIEGO WRITER
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