Hello, I’m Gyegyopon.
The Geminid meteor shower active in mid-December is one of the “three major meteor showers,” reliably delivering numerous meteors every year.
You can see many meteors from locations with clear stargazing conditions, and even the bright skies of cities offer a decent number of sightings.
This article summarizes the 2025 Geminid meteor shower conditions and provides information about meteors.
I hope this article proves helpful for those who wish to see meteors or learn more about them.
Main text
For those who want a quick overview of this year’s Geminid meteor shower, please read the “Summary.”
Starting from “What is the geminid meteor shower?”, I explain the “Summary” content in a bit more detail.
If you want to learn more about meteors, please continue reading from “What are meteors?” onwards.
Summary
The 2025 Geminid meteor shower is expected to peak around 5:00 PM on December 14. In Japan, the Geminid meteor shower will be best visible after midnight. Since the peak time is far from midnight, conditions from the perspective of peak timing are not ideal. On the other hand, regarding the moon’s influence, the moon will be not very full (not very bright). Furthermore, until the moon rises after midnight, observers can see meteors against a dark sky free from the moon’s influence, making conditions favorable.
To see the 2025 Geminid meteor shower, it’s best to watch on any of the three nights from the evening of December 12th to the morning of the 15th (or all three nights, of course).
On each night, the number of meteors is expected to increase around 9 PM, peaking after midnight.
However, this year the moon will rise after midnight. The moon’s brightness makes meteors harder to see, so the period before moonrise should offer better viewing conditions.
Of the three nights, the most meteors are expected to be visible just after midnight on the 13th (as the date changes to the 14th). In a dark sky location with good stargazing conditions, up to about 45 meteors per hour should be visible.
Additionally, on the night of the 14th to the 15th, around midnight, up to about 35 meteors per hour should be visible.
You don’t need to worry about where in the sky to look. Meteors appear in all directions. After the moon rises, it’s best to look in a direction where the moon isn’t directly in your field of view.
The best places to view meteor showers are locations with dark skies (where many stars are normally visible) and a wide, unobstructed view of the sky. It’s best to stay as far away from large cities as possible.
What is the Geminid Meteor Shower?
The Geminid meteor shower is an annual meteor shower active in mid-December. The three meteor showers where many meteors can be seen are collectively called the “Three Major Meteor Showers,” and the Geminids are one of them. The other two of the Three Great Meteor Showers are the Quadrantid meteor shower in January and the Perseid meteor shower in August.
The Geminid meteor shower reliably produces a large number of meteors each year1, and since it occurs at a relatively early hour, it is a fairly easy meteor shower to observe.
However, the fact that it peaks during a very cold time of year might be a bit challenging.
This year’s Geminid meteor shower
The peak of the 2025 Geminid meteor shower2 occurs around 5:00 PM on December 14th3. In Japan, the best viewing time for the Geminids is around 2:00 AM. This year, the peak time and the optimal viewing time are quite far apart, making conditions less than ideal.
Regarding the moon, the last quarter (half moon) in 2025 occurs on December 12th. While moonlight may be a concern after moonrise, the moon doesn’t rise until after midnight 4, so until then, you can see meteors under good conditions without the moon’s interference. Also, the moon isn’t very full (bright), so even after it rises, you should still be able to see a decent number of meteors.
While peak condition isn’t ideal, the 2025 Geminid meteor shower can be described as “fairly decent” since meteors can be seen in the dark night sky until the moon rises.
The night of December 13th to 14th is expected to offer the highest number of visible meteors. In a dark sky location with good stargazing conditions, around 25 meteors per hour should be visible around 9 PM, increasing to about 45 per hour around 1 AM when the peak occurs. Even after moonrise, 35 to 45 meteors per hour can still be expected.
Additionally, on the nights of the 12th and 14th, you should be able to see many meteors, though not as many as on the night of the 13th. On the night of the 12th, you can expect to see up to about 20 meteors per hour, and on the night of the 14th, about 35 meteors per hour.
(This isn’t limited to this year alone) The Geminid meteor shower typically begins appearing once the sky darkens, with numbers gradually increasing around 9 PM and peaking after midnight. While observing after midnight offers the best chance to see a relatively large number of meteors, it’s even fine to start watching earlier if that’s more convenient.
Direction where meteors can be seen
Meteors appear in various directions across the sky. Although it’s called the “Geminid Meteor Shower,” meteors don’t appear only in the direction of the constellation Gemini.
Meteors from a meteor shower have a distinctive appearance.
They appear to radiate outward from a single point in the night sky called the “radiant.” Since the radiant is near the constellation Gemini, this shower is called the “Geminids.”
Meteors appearing near the radiant point are moving toward us, so their paths appear short and they seem to move slowly. Meteors appearing at a distance from the radiant point are seen from the side as they move, so their paths appear long and they seem to move quickly.
When you spot a meteor in the night sky, if you extend its path backward and it intersects the radiant point, it is highly likely to be a meteor from the Geminid meteor shower.5. Conversely, meteors moving in other directions are not part of the Geminids, even during Geminids’ active period6.
How to Observe Meteors
To see lots of meteors, try to watch from a place where the sky is as dark as possible (where you can usually see lots of stars). If the sky is bright, faint meteors get lost in the brightness and become invisible, reducing the number you can see.
So, where are these “dark sky” locations? Roughly speaking, the farther you are from large cities, the darker the sky becomes. Large cities have a lot of artificial light, and this light illuminates the sky, making it brighter.
Even if you’re observing within or near a large city, it’s best to find a spot with as little nearby light pollution as possible.
Having a wide view of the sky is also important. Since meteors appear in various parts of the sky, a wider field of view increases the chances of spotting one.
You can look in any direction. When the moon is out, it’s best to look in a direction where the moon isn’t directly in your field of vision.
No special equipment is needed to observe meteors. Observe them with the naked eye.
Using binoculars or a telescope narrows your field of view considerably, making it difficult to catch meteors that appear unpredictably.
It takes time for your eyes to adjust to the dark. After entering a dark place, allow about 15 minutes for your eyes to adjust. During this time, avoid looking at bright objects like smartphone screens.
Standing and staring at the sky for a long time is very tiring.
Bring a picnic blanket or similar and lie down to watch the sky—it makes observation much easier. (Just try not to fall asleep; maybe take a nap during the day beforehand.)
Staying still outdoors will make you feel the cold intensely. I recommend bundling up to the point where you think you’re overdressing. Using a portable heater or getting into a sleeping bag are also good options.
Please don’t push yourself too hard.
Also, shouting loudly at night or entering restricted areas can cause trouble, so please follow the rules and etiquette. Since you’ll be moving around in the dark, be careful to avoid accidents.
What are meteors?
Now, let me explain in a bit more detail.
A meteor is a phenomenon where dust particles, like grains of sand flying through space, enter Earth’s atmosphere at high speed and glow.
Generally, meteors in meteor showers originate from dust particles ejected by comets. However, the Geminids are an exception; the celestial body that released the dust particles is believed to be an asteroid called “Phaethon (3200 Phaethon),” not a comet. (The original celestial body is called the “parent (celestial) body.”) Dust particles ejected from the parent body spread out along its entire orbit. Each year, when Earth passes through this region, the dust particles plunge into Earth’s atmosphere.
7.
This is why meteors from the same meteor shower appear around the same time each year.
Since all dust particles come from the same direction, observers see meteors appearing to radiate out from a single point. This central point from which meteors appear to radiate is called the “radiant.” The radiant is a conceptual point (imagined in the mind), so nothing can be seen there when you gaze intently at the night sky.
If a meteor happens to appear at the radiant, it looks like a light appears, stays still, and then fades away. Such a meteor is called a “stationary meteor.” A stationary meteor is one that appears to be coming straight toward you.
Number of meteors
The number of meteors visible depends not only on the activity level of the meteor shower itself, but also on the altitude of the radiant point at the observation site and the brightness of the sky.
Activity of meteor shower itself
The dust particles spread along a comet’s orbit contain dense (clumped) regions and sparse (scattered) regions. If Earth plunges into a dense region, numerous dust particles will enter the atmosphere, resulting in a large number of meteors appearing.
An increase in the number of dust particles entering the atmosphere, leading to more meteors appearing, is described as “the meteor shower becoming active.”
Roughly speaking, dust particles form a cylindrical envelope around the parent celestial body’s orbit, with the dust becoming denser toward the center. Therefore, as Earth approaches the center of the dust cloud, meteor shower activity intensifies, peaking at the densest section. After the peak, the dust particles gradually become sparser, and the meteor shower activity subsides.
Radiant altitude
If the activity level of a meteor shower remains constant, the higher the radiant point rises in the sky, the greater the number of meteors visible.
The Geminid meteor shower tends to increase in number around 9 PM, peaking after midnight, because the radiant point reaches its highest point in the sky after midnight.
The primary reason the number of meteors increases as the radiant’s altitude rises is due to the difference in the range from which dust particles enter.
Consider the same number of dust particles arriving directly overhead versus arriving at an angle. When particles arrive at an angle, the same number of particles are spread over a larger area. Consequently, fewer meteors are observed8.
.
When the radiant is below the horizon, meteors do not appear9.
Brightness of sky
The darker the sky (where many stars are visible), the more meteors you can see. Conversely, in a sky where only a few stars are visible (a bright sky), the number of meteors you can see decreases because faint meteors become invisible.
Besides differences in sky brightness due to location, the moon also affects how bright the sky appears.
When the moon is very thin, its effect is minimal, but as the moon waxes, it grows brighter. It reaches its peak brightness at full moon, and under a full moonlit sky, only fairly bright meteors will be visible.
For the Geminid meteor shower, observing under skies where stars as faint as magnitude 1 are visible will yield over two and a half times as many meteors10.
Parent body of Geminid meteor shower
Most parent bodies of meteor showers are comets. Comets are composed of ice and rock (dust particles) mixed together, often described as “dirty snowballs.” As a comet approaches the Sun, the ice sublimates into gas, releasing dust particles along with it. These dust particles plunge into Earth’s atmosphere, becoming meteors. Asteroids, on the other hand, are composed of rock and iron and do not release dust particles.
The parent body of the Geminid meteor shower is thought to be Phaethon. Phaethon was discovered as an asteroid in 1983.
Since Phaethon’s orbit coincides with the orbit of the dust particles responsible for the Geminid meteor shower, it was hypothesized that Phaethon might be the parent body. At that time, no dust emission was observed from the asteroid Phaethon itself. However, it was thought that it likely once emitted dust as a comet but has since ceased emission, possibly due to ice depletion or some other reason.
In 2009, NASA’s Solar Observatory “STEREO” observed Phaethon displaying a short tail near its perihelion (the point in its orbit closest to the Sun). Since Phaethon’s tail was also observed in 2012 and 2016, it is now believed that Phaethon, while low in activity, still exhibits cometary activity.
However, observations from NASA’s “Parker Solar Probe” in 2018 indicated that the amount of material Phaethon could release was too small to be the source of the Geminids meteor shower. Furthermore, in 2022, observations from the “Solar and Heliospheric Observatory (SOHO)” revealed that Phaethon’s tail is composed not of dust particles, but of sodium gas.
So, how exactly were (or are) the dust particles that form the Geminid meteor shower supplied? To solve this mystery, JAXA is planning to launch the “DESTINY+” probe. The DESTINY+ probe is scheduled to approach Phaethon to within about 500 km over a period of approximately two years after launch. During a brief encounter, it will photograph Phaethon’s surface and analyze the surrounding dust particles.
(Originally planned for launch in fiscal year 2024, the DESTINY+ launch has been postponed to fiscal year 2028.)
Related Information
References
Information referenced
- National Astronomical Observatory: Geminid Meteor Shower Reaches Peak (December 2025)
- IMO (International Meteor Organization)：2025 Meteor Shower Calendar (English) (Refer to peak period, brightness ratio)
- Shigeo Uchiyama: Method for Calculating Meteor Sighting Data (Refer to Differences in Meteor Counts Based on Radiant Altitude)
- National Astronomical Observatory: Koyomi Station (Calendar Calculations) (You can look up moonrise and sunrise times for various locations)
- JAXA：
- NASA：Asteroid’s Comet-Like Tail Is Not Made of Dust, Solar Observatories Reveal (English)
Others
脚注
- The Perseid meteor shower is also reliable. The Quadrantid meteor shower varies significantly from year to year.
- “Peak” refers to the time when the meteor shower is most active.
- The Geminids peak annually around solar ecliptic longitude 262.2 degrees. The term “solar ecliptic longitude” may sound like it refers to the Sun, but it actually indicates the position of Earth as it orbits the Sun. It measures the angular distance Earth has traveled from a specific point called the vernal equinox, with the Sun at the center.
- On December 14th, moonrise times are 1:14 AM in Tokyo and Sapporo, and 1:51 AM in Fukuoka.
- However, it is not a 100% certain method of identification, as meteors not from the Geminids may occasionally move in a similar direction.
To identify it with certainty, observe the meteor from two or more locations. Using the principle of triangulation, you can determine the meteor’s three-dimensional path and speed. Extend this path into space. If the original dust particle shares the same orbit as its parent body, you can conclude it belongs to that meteor shower. - Meteors not belonging to a specific meteor shower are called “sporadic meteors.”
- Therefore, only celestial bodies whose orbits intersect Earth’s can become parent bodies for meteor showers.
- If the radiant’s altitude is θ degrees, the area over which the same number of particles enter the atmosphere expands to (1/sin θ) times the area when the radiant is at the zenith (directly overhead).
For example, if the radiant’s altitude is 30 degrees, the atmospheric area into which the same number of dust particles enter doubles, so the number of meteors is halved. (The right diagram is drawn assuming a radiant altitude of 30 degrees.) - When the radiant is just below the horizon, meteors may appear, though their number is very small.
- The numerical value representing “how many times more meteors are visible under skies where stars as faint as magnitude 1 are visible” is called the “luminosity ratio.” For example, suppose you observe a meteor shower with a luminosity ratio of 2 and see 10 meteors under skies where stars as faint as magnitude 3 are visible. Then, if observed under skies where stars as faint as magnitude 4 are visible, 10 × 2 = 20 meteors would be expected. Under skies where stars as faint as magnitude 6 are visible, 10 × 2 × 2 × 2 = 80 meteors.
The Geminid meteor shower has a luminosity ratio of 2.6.
