Here are the astronomical events occurring in the month of May: (All times are given in UTC format)
- May 5: The Eta Aquarids meteor shower will peak.
- May 7: Mercury will reach its highest point at 21.2 degrees away from the sun. It will start to descend back into the sun at this point.
- May 19: The Moon will occult Aldebaran at approximately 2:53 UTC. It is best seen in North America.
- May 20: Comet C/2014 Q1 PANSTARRS may become visible in binoculars.
- May 20: Io and Ganymede will cast their shadows on Jupiter in a double-transit event at 22:04 – 22:53.
- May 21: Callisto and Europa will also cast their shadows on Jupiter in another double-transit event at 11:26 – 11:59.
- May 23: Saturn reaches opposition at approximately 1:00.
- May 24: Asteroid 1669 Dagmar will occult Regulus at approximately 16:47. Best seen in the Arabian Peninsula. This will be the brightest asteroid star occultation in 2015.
- May 28: Ganymede and Io will cast their shadows again in a double-transit event at 00:01 to 2:18.
- May 30: Comet 19/Borrelly may become visible with binoculars.