when is the green comet passing earth

The next green comet passing near Earth will be Comet C/2025 K1 (ATLAS). It will make two close approaches: the first on August 13, 2025, at about 0.58 AU (astronomical units) from Earth, though it will be faint and mostly visible from the Southern Hemisphere with large telescopes. The comet reaches perihelion (closest to the Sun) on October 8, 2025, when it may brighten significantly. Its closest approach to Earth is on November 24, 2025, at 0.40 AU, when it will be more easily visible from both hemispheres, potentially bright enough for binocular observation. There is also another comet, C/2025 A6 (Lemmon), passing close to Earth at about 0.6 AU on October 21, 2025, notable for northern hemisphere observers. However, the classic "green comet" that had attention recently was Comet C/2022 E3 (ZTF), which passed near Earth in early 2023, its closest approach about 26 million miles away, last seen around late January to early February 2023. This comet is now not near Earth. For 2025, the most relevant greenish comet nearest to Earth is C/2025 K1 (ATLAS), with important visibility dates in August, October, and November 2025.