Mercury is the closest planet to the Sun and also the speediest planet in the Solar System.
Like Venus, it orbits between Earth and the Sun, and is known as an inner – or 'inferior' – planet.
It's been rather tricky to see Mercury in February and March 2025, but this evening, 8 March, is your best chance yet.
You'll see it in the western sky about 30 minutes after sunset (which happens around 6pm on 8 March), and Mercury should have set by around 8pm, UK time.
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Venus is shining brightly above Mercury at the moment, so you may be tempted to think you're observing Mercury if you spot Venus.
If the bright 'star' you're looking at is very obvious to the naked eye and visible long after sunset, chances are you're actually seeing Venus.
Try and catch Mercury as soon after the Sun sets as possible.
Get more advice with our guide on how to observe Mercury.
Why Mercury is best tonight
Mercury whips round the Sun at speeds of up to 47km per second; fast compared to Earth’s orbit of 30km per second.
Because it orbits so close to the Sun, Mercury always appears near the Sun in the sky, and is often swallowed by its glare.
This means caution should be taken when observing Mercury, particularly if doing so through binoculars or a telescope.
Always make sure the Sun has properly set when observing Mercury.
Mercury's visibility from Earth is dependent on how far away from the Sun it happens to be.
It can be a morning or an evening object, often appearing in the dusk or dawn twilight.
The best time to view Mercury is during greatest elongation, which is simply an astronomical term describing the point at which Mercury is farthest from the Sun in its orbit.
At this time, Mercury is placed far to either the east or west side of the Sun, and these are known as eastern or western elongations.
When positioned at the eastern side of the Sun, Mercury appears in our evening skies; when at the western side it appears in early morning skies.
Tonight, 8 March, Mercury reaches greatest eastern elongation, and this is why it's the best day to see it during the current period of observing.
The planet reaches its highest altitude of 15 degrees in the evening sky above the western horizon (although this will vary depending on your location).
Find yourself a flat, clear western horizon to give yourself the best chance of seeing it, between the Sun setting and Mercury itself setting.
If you miss it or are clouded out, don't fret! Try again at the same location at the same time over the coming nights: it will still be visible.
But be quick. By the end of March, Mercury will no longer be visible in the evening sky.
If you observe or photograph Mercury this month, let us know by emailing contactus@skyatnightmagazine.com.
