Moon

The moon is a celestial body that appears during the Minecraft night.

Nighttime
Nighttime begins after the sun has fully set in the west and the moon has risen in the east. As time passes, the moon will slowly move westward across the sky. Overall, nighttime lasts about 7 minutes (in real time). Players can track the moon's position in the sky using a clock.

During the night, the moon illuminates the surface in the same manner as the sun; however, light levels will fall to a minimum of four. This allows hostile mobs such as zombies and creepers to spawn. To prevent spawning, you can swap the difficulty to peaceful or turn off the day-night cycle.

Grass blocks and saplings will not grow in moonlight, nor will they decay. To grow them at night requires the use of light sources such as torches. On the other hand, crops will continue to grow.

Nighttime can be skipped entirely using a bed, provided there are no monsters nearby.

Stars
Together with the moon, the night sky also consists of stars. Stars appear as bright points, and the starfield rotates with the moon as the night progresses. Because they rise in the east and descend in the west, you can navigate by the stars even when the moon is not visible.

Phases
The Moon goes through eight lunar phases, and changes phase every night. This allows the player to keep rough track of the passage of time, even after spending a few game days underground.



The phases are (in chronological order as they appear in-game):

Full Moon Waning Gibbous Last Quarter Waning Crescent New Moon Waxing Crescent First Quarter Waxing Gibbous

There is no explicit command to change the moon's phase, but using will advance time by one day, and therefore to the next phase. To go back one phase, using will advance time by 7 days, which is one full lunar cycle minus one moon phase.

Effects on mobs


The phase of the moon has two subtle effects on mob spawning:


 * The number of slimes that spawn in swamps is proportional to the moon's fullness: They are most numerous during the full moon, and none will spawn during the new moon. (The moon's phase does not influence the normal spawning of slimes in designated chunks at altitudes below y=40.)
 * The fuller the moon, the higher the chance skeletons and zombies have to pick up items and spawn with weapons and armor. Furthermore, there is a higher chance for their equipment to be enchanted, and if it is the enchantment levels will be higher.  A fuller moon also gives spiders a higher chance to spawn with random beneficial status effects, including invisibility. All of these effects combine with the world's difficulty, with higher difficulty levels increasing the chance of mob buffs.

Trivia

 * One Minecraft lunar cycle (from full moon to full moon) takes 2 hours 40 minutes of play time. This means there are approximately 9 lunar cycles in one real-world day (24 hours) of play.
 * Whereas the moon moves independent of other celestial bodies in real life, the Minecraft moon is fixed in the sky relative to the stars.
 * Thus, solar eclipses are currently impossible in Minecraft.
 * Standing or flying at a height above the terrain of approximately 1.4x the render distance, the sun will appear opposite to the moon in the sky, making it seem almost as if the player is in space.
 * The moon appears to be lit from the north or south, whereas it should be lit from the east or west (by the sun).
 * For that matter, being fixed opposite to the sun, it should be constantly full and should result in a total lunar eclipse every night at midnight.
 * The star pattern is based on a seed, but not the current world's seed. Like the bedrock pattern, the stars are always based on the same seed, no matter the seed of the world.
 * The eight lunar phases actually occur in reverse sequence in the game, from New Moon, then Waning Crescent, then 3rd/Last Quarter, then Waning Gibbous, then Full Moon, and so on. (Note that in the gallery image they are in the correct natural order.)