Mercury is our sun’s innermost planet. So it always lies near the sun in our sky. Mercury is now in the west after sunset. This small, speedy planet will reach its greatest elongation, its greatest apparent distance from the sun in our sky, today, October 29, 2025. And it’ll be near the red planet Mars. Look for them both in the evening twilight.
Mercury after sunset in October 2025
Where to look: Look west, in the sunset direction – shortly after sunset – for Mercury. And Mars will be nearby shining at 1.5 magnitude. Look for them in the western evening twilight. This will be the best evening apparition of Mercury for the Southern Hemisphere in 2025.
Greatest elongation: Mercury is farthest from the sun on our sky’s dome at 22 UTC (5 p.m. CDT) today. At that time, Mercury will be 24 degrees from the sun in our sky. See A comparison of elongations, below.
Brightness: Mercury emerged in the evening sky early in October. Since then, it’s been shining at around -0.2 magnitude. At greatest elongation it’ll be farther from the sunset glare and still brighter than most stars! In the evenings after greatest elongation, the innermost planet will rapidly fade as it starts to move between Earth and the sun, meaning its illuminated side will become less and less visible. It’ll disappear next month and will reach inferior conjunction – when it passes between Earth and the sun – at 9 UTC on November 20.
Through a telescope: Mercury will appear about 63% illuminated at greatest elongation. It’ll measure 6.62 arcseconds across.
Constellation: Mercury will lie in front of the constellation Scorpius the Scorpion at this elongation. Doubtless, most of the stars in this constellation will be lost in the twilight.
Note: As the innermost planet, Mercury is tied to the sun in our sky. As a result, it never ventures very far above the horizon after sunset. So as soon as the sun disappears below your horizon, your clock starts ticking. Will you see the glowing point of light that is Mercury before it drops below the horizon, following the setting sun?
For precise sun and Mercury rising times at your location:
Old Farmer’s Almanac (U.S. and Canada)
timeanddate.com (worldwide)
Stellarium (online planetarium)
October chart for the Southern Hemisphere
Mercury events in 2025
Note: Times are in UTC
Feb 9, 2025: Superior conjunction (passes behind sun from Earth)
Mar 8, 2025: Greatest elongation (evening)
Mar 24, 2025: Inferior conjunction (races between Earth and sun)
Apr 21, 2025: Greatest elongation (morning)
May 30, 2025: Superior conjunction (passes behind sun from Earth)
Jul 4, 2025: Greatest elongation (evening)
Aug 1, 2025: Inferior conjunction (races between Earth and sun)
Aug 19, 2025: Greatest elongation (morning)
Sep 13, 2025: Superior conjunction (passes behind sun from Earth)
Oct 29, 2025: Greatest elongation (evening)
Nov 20, 2025: Inferior conjunction (races between Earth and sun)
Dec 7, 2025: Greatest elongation (morning)
Heliocentric view of Mercury October 2025
A comparison of elongations
In October 2025, Mercury stretches out 24 degrees from the sun in our sky. In fact, the farthest from the sun that Mercury can ever appear on the sky’s dome is about 28 degrees. And the least distance is around 18 degrees.
Mercury (and Venus) elongations are better or worse depending on the time of the year they occur. So in 2025, the Northern Hemisphere will have the best evening apparition in March. And the Southern Hemisphere will have its best evening elongation of Mercury in late October.
In the autumn for either hemisphere, the ecliptic – or path of the sun, moon and planets – makes a narrow angle to the horizon in the evening. But it makes a steep slant, nearly perpendicular, in the morning. So, in autumn from either hemisphere, morning elongations of Mercury are best. That’s when Mercury appears higher above the horizon and farther from the glow of the sun. However, evening elongations in autumn are harder to see.
In the spring for either hemisphere, the situation reverses. The ecliptic and horizon meet at a sharper angle on spring evenings and a narrower angle on spring mornings. So, in springtime for either hemisphere, evening elongations of Mercury are best. Meanwhile, morning elongations in springtime are harder to see.
More Mercury evening elongation comparisons for 2025
Bottom line: The sun’s innermost planet, Mercury, will lie 24 degrees from the sunset when it reaches its greatest elongation at 22 UTC today, October 29. Also, this is the best evening apparition of Mercury in 2025 for the Southern Hemisphere.
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Read about greatest elongations, superior and inferior conjunctions: Definitions for stargazers
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