Mercury at perihelion May 2026: All you need to know

Mercury at perihelion in May 2026

When it occurs: Mercury will reach perihelion—the closest point to the sun in its elliptical orbit—on May 18, 2026, at 10:00 UTC (6:00 a.m. EDT).

Meaning: The word perihelion comes from Ancient Greek, where peri means “near” and helios means “sun,” more specifically the sun god in Greek mythology.

Distance from the sun: Mercury has the most elliptical orbit of all the planets in our solar system, with an eccentricity of 0.206. As a result, its distance from the sun varies significantly between its aphelion and perihelion.

At perihelion on May 18, 2026, Mercury will be 0.30755 AU (about 46 million km) from the sun. The average distance between the sun and Mercury is about 0.387 AU or 57.9 million km.

Distance from Earth: At perihelion on May 18, 2026, Mercury will be 1.30705 AU (about 195.5 million km) from Earth.

Speed at perihelion: According to Kepler’s second law of planetary motion, planets travel faster when they are closer to the sun (near perihelion).

At perihelion, Mercury travels at its fastest speed—about 59.0 km/s, or 212,400 km/h.

Mercury’s perihelion and seasons: Mercury doesn’t have seasons like Earth because its axial tilt is almost zero (about 0.01°). Instead, it experiences so-called “thermal seasons” due to its highly elliptical orbit.

Mercury gets hotter when it reaches perihelion because its perihelion is about 1.5 times closer to the sun than its aphelion.

How often does Mercury reach perihelion?

Mercury takes about 88 days to orbit the sun, so it reaches perihelion once every 88 days. This interval is called Mercury’s sidereal period.

Mercury at perihelion in 2026

Here are the dates of perihelion of Mercury in 2026:

Please bookmark Spaceandtelescope.com or follow us on Facebook and Twitter to get latest space news, upcoming skywatching events and astronomy-related content.