Look up! What's going on in the May night sky?
See meteors from Halley's Comet and this year's final micromoon
Eyes to the sky for the month of May, for a chance to spot pieces of Halley's Comet streaking by overhead.
Here is the Astronomical Guide to May 2025:
May 3-4 — Mars near the Waxing Crescent Moon
May 4 — First Quarter Moon
May 5-6 — eta Aquariid meteor shower peaks
May 12-13 — Full Flower Moon
May 20 — Last Quarter Moon
May 22-24 — Waning Crescent Moon near Saturn and Venus
May 27 — New Moon
May 28 — eta Aquariid meteor shower ends
May 31 — Mars near the Waxing Crescent Moon
Visit our Complete Guide to Spring 2025 for an in-depth look at the Spring Forecast, tips for planning for it and much more!
The Moon
The astronomical events for May 2025, including the phases of the Moon, planetary conjunctions, and meteor showers. (Scott Sutherland, moon graphics from NASA's Scientific Visualization Studio, conjunctions courtesy Stellarium)
The Waxing Crescent Moon will be in the western sky from the first to the third of the month, in the hours just after sunset. Look on the night of the 3rd to see it near the planet Mars and the Beehive Cluster.
The First Quarter Moon is on the 4th, with a Waxing Gibbous Moon passing through our skies each night after until the Full Flower Moon on the night of the 12th to 13th.
This Flower Moon is the final micromoon of 2025. As this Full Moon is farther away from Earth than a typical Full Moon, it will appear smaller and dimmer in the sky. Check it out just after sunset or just before sunrise, though, for it to look substantially larger, thanks to the mysterious Moon Illusion.
Passing through its Waning Gibbous phase from the 13th to the 19th, the Last Quarter Moon will occur on the 20th.
The Waning Crescent Moon can then be seen in the predawn sky each morning from the 21st through the 26th. Check it out, low in the sky along the eastern horizon, on the mornings of the 22nd through 24th to catch it passing by the planets Venus and Saturn.
The Crescent Moon passes by the planets Venus and Saturn in the predawn sky from May 22nd through 24th. (Stellarium/Scott Sutherland)
The New Moon is on the 27th, giving us our darkest skies of the month. It's a great time for stargazing!
After which the cycle begins again as the Waxing Crescent Moon will once again grace our evening skies until the end of the month. See it near the planet Mars again on the night of the 31st.
DON'T MISS: What's in the sky this Spring?
The Constellations
Spring Constellations dominate the night sky during the month of May.
To the south, Gemini, Cancer, Leo, Virgo, Libra, Serpens/Ophiuchus, and Aquila are visible in the evening sky each night, with Hydra stretching across much of the horizon as well.
The constellations in the southern sky at midnight on May 15, 2025. (Stellarium)
After midnight, Sagittarius, Capricornus, and Aquarius follow along, with Pisces rising towards dawn.
To the north, Cassiopeia, Ursa Major ("The Big Dipper"), and Ursa Minor ("The Little Dipper") remain the easiest constellations to pick out, as they circle the north celestial pole.
The constellations in the northern sky at midnight on May 15, 2025. (Stellarium)
Cygnus, Hercules, Boötes, and Draco also feature prominently.
SPACE WEATHER: Geomagnetic storms — When should we look up and when should we worry?
eta Aquariid meteor shower
Back on April 19, Earth crossed into a stream of dusty debris in space, left behind by famous Halley's Comet. This began the yearly eta Aquariid meteor shower.
Although it started off slowly through the latter half of April, this shower quickly reaches its peak once we transition into May. According to NASA, the best time to view the eta Aquariids is between May 3rd and 9th. However, the morning of May 6 is when the meteor shower peaks.
The radiant of the eta Aquariid meteor shower — the location in the sky where the meteors appear to originate from — in the predawn hours of May 6, 2025. (Stellarium/Scott Sutherland)
The 'radiant' of the shower only crests the eastern horizon just after 3 a.m., local time. As a result, the eta Aquariids are definitely an 'early riser' meteor shower, and it only offers a short window each morning to see it.
During the peak, from around 3 a.m. through morning twilight on the 6th, observers with a clear, dark sky could see anywhere from 20-40 meteors per hour.
Give yourself about 20 minutes without any exposure to bright light (including your smartphone) for your eyes to adjust to the dark. Then, look straight up, taking in as much of the sky above as possible, as their brief flashes can show up at any point overhead.
Urban light pollution will reduce the number of visible meteors, as the glare of illumination from buildings, street lights, and signs 'washes out' the sky, so only the brightest meteors can shine through.
Fortunately, with the Waxing Gibbous Moon setting in the west just as the eta Aquariid radiant rises in the east, the sky should be free from lunar light pollution, providing excellent viewing conditions for the show. However, check your weather forecast before going out, to ensure that the sky above you isn't overcast, so at least some portion of the sky is available to watch for meteors.
READ MORE: How to get the most out of meteor showers and other night sky events
One fascinating phenomenon we can see with the eta Aquariids is 'persistent trains' — a glowing trail left behind after a meteor winks out, which can persist in the air for anywhere from minutes to hours.
Four frames taken from a persistent train video, shot on October 21, 2022, show the initial Orionid meteor flash, and three views of the persistent train that developed in its wake. (Brenda Tate/Tim Doucette/UGC)
Exactly what causes persistent trains is still something of a mystery. Meteor scientists (meteoriticists) have some hypotheses, but the phenomenon has been difficult to study in detail, as it has only rarely being captured on camera.
Although the eta Aquariids peak early in the month, this shower has a very long 'tail' to it. Even though NASA recommends seeing the shower up until the 9th, we can still spot bits of Halley's Comet occasionally streaking through the predawn sky right up until Earth exits the comet's debris stream on May 28.