Day and night cycle



The day and night cycle of the Terraria world refers to the rising and setting of the Sun and Moon, and the ways this can affect the world.
 * Day begins at 4:30 a.m., while night begins at 7:30 p.m.
 * Day and Night each have their own respective theme music in some surface biomes.
 * Some surface enemies only spawn at night (see Enemies below).
 * Some NPCs sell unique items at night, like the Arms Dealer, who sells Illegal Gun Parts at night.

Note that the sun in Terraria rises at the left of the map, even though the left is referred to in-game as "West" (the same for right/East), E.g. when a Goblin Army, Frost Legion, or Pirate Invasion begins approaching.

Time

 * All newly-created Worlds begin at 8:15 a.m.
 * One minute of in-game time lasts one second of real-world time, meaning one hour in-game lasts one minute real-world. One Terraria day therefore lasts, 15 real-world minutes, and night lasts 9 real-world minutes.
 * In-game time can be displayed:
 * A placed Grandfather Clock will display time for all players within ~80 tiles horizontal and ~50 tiles vertical of the clock.
 * On, by having a Watch, GPS, PDA or Cell Phone in the player's inventory.
 * By applying Time Hair Dye.
 * Time can be sped up to the end of the current cycle once every seven days, using the.

Mobile Time
The features a different day/night cycle that occurs at a dynamic rate. In order to accommodate the shorter play times that mobile game sessions tend to entail, day and night last for shorter overall periods, and boss or event fights can cause the day or night period to extend in order to offer players more time to complete them. However once Hardmode begins, the day and night cycle will progress at the same speed as in other versions.

Enemies
At the surface layer, unique enemies spawn at night. Nocturnal enemies will run or fly away when the day starts.

Additionally, Eye of Cthulhu, Skeletron, The Twins, The Destroyer, Skeletron Prime and can only be summoned at night.

In contrast, King Slime can only spawn randomly during the day, though it can be summoned with the Slime Crown at any time.

Night-only enemies

 * Demon Eye
 * Raven (only during Halloween)
 * Zombie
 * Blood Zombie (during a Blood Moon)
 * Drippler (during a Blood Moon)

Night-only Hardmode enemies

 * Clown (during a Blood Moon)
 * Hoppin' Jack (only during Halloween)
 * Possessed Armor
 * Wandering Eye
 * Werewolf (during a Full moon)
 * Wraith

Trivia

 * You can grab the sun or the moon on the title screen and move it around.
 * Before formal server software was released for Terraria, and while it was necessary to open a second window of Terraria to host a server, you could drag the sun or moon around to directly change the time of day within the server.
 * If you are wearing sunglasses, the sun will appear to be wearing them too. Un-equipping the sunglasses will cause it to revert back. This has no functional effect.
 * On, the sun still has its old sprite.
 * Internally, the time counter is reset to zero at both dawn and dusk. During daytime, the counter is allowed to go up to 54000, and during nighttime it is only allowed to go up to 32400.
 * Despite the sun and moon both always being on opposite sides of the sky, there are still moon phases (there can be a new moon even though the moon is not visible).