Blood moon is the popular name for the Moon during a total lunar eclipse, when it turns red or copper. Sunlight bending through Earth's atmosphere still reaches it, but the air scatters away most blue light, so mainly red light gets through, the same effect that reddens sunsets. Dust and cloud set how dark it looks.
Understanding Blood Moon
Why the eclipsed Moon turns red
Seen from the Moon during totality, Earth is a black disc ringed by a thin, glowing red line: every sunrise and sunset on the planet at once. Earth's atmosphere bends that light into the shadow like a weak lens, and on its long path through the air most of the blue is scattered away, leaving red and orange. The centre of the umbra usually gets less of this light than its edge, so one side of the Moon often looks brighter than the other, and the colour shifts as the Moon moves through the shadow.
The next blood moons
The next three total lunar eclipses, each with its own page and local times. The last was on 3 March 2026.
| Date | Totality | Seen from |
|---|---|---|
| 31 December 2028 | 1 h 12 min | Asia, Australia, the Middle East, East Africa; Europe at moonrise |
| 26 June 2029 | 1 h 42 min | The Americas, Africa; western Europe as the Moon sets |
| 20 December 2029 | 55 min | Europe, Africa, the Middle East, South Asia; the eastern Americas at moonrise |
The Danjon scale
Devised by the French astronomer André Danjon, the scale rates how dark and how red the Moon looks at mid-totality:
| Rating | How the Moon looks |
|---|---|
| L0 | Very dark, almost invisible at mid-totality |
| L1 | Dark grey or brownish, details hard to make out |
| L2 | Deep red or rust, with a very dark centre and a brighter edge |
| L3 | Brick red, often with a bright yellowish rim |
| L4 | Bright copper or orange, with a very bright bluish rim |