Daylight cycle

The day/night cycle is a 20 minute long lapse between two main light settings.

Daytime
Daytime is the longest section of the cycle, lasting 10 minutes.
 * When a player first spawns in Infdev, Alpha, and Beta the cycle will always start right at the beginning of daytime.
 * Daytime features the Sun, and a light blue sky.
 * During daytime, all blocks that are in direct vertical view of the sky receive daylight, the strongest light possible, which is light level 15.
 * Daylight provides ample light for the growth of all trees and crops.
 * Zombies and Skeletons in direct view of the sky (and not in water or ice) during daytime will be set on fire.

Sunset
Lasts 1 ½ minutes.
 * A period between daytime and nighttime, when the Sun sets on the West horizon, and the Moon rises on the East horizon.
 * All blocks that are in direct vertical view of the sky get 1 shade of lighting darker every 10 seconds.
 * The sky near the setting sun will have a red glow when the sun sets.
 * Actual time of Sunset will not change if the texture for the sun is changed. The day/night cycle will be the same length with the same effects even if the sun is visibly larger or smaller.

Nighttime
Lasts 7 minutes.
 * During nighttime the world is covered in darkness with a light level of 4, and hostile mobs may spawn on the surface.
 * Nighttime features the Moon, and a dark black sky, with white stars.

Sunrise
Lasts 1 ½ minutes.
 * A period between nighttime and daytime, when Moon sets on the West horizon, and the Sun rises on the East horizon.
 * All blocks that are in direct vertical view of the sky get 1 shade of lighting brighter every 10 seconds.
 * The sky will have a red glow when the sun rises.

Clock
In the Halloween Update, Notch added a clock that lets you tell the time in the "Minecraft" world. It's crafted like this:



''Note: The clock will not work in the Nether, due to the fact that the Nether does not receive Day or Night.'

Trivia
In the Minecraft sky, the Sun and Moon always appear in the same position relative to the stars. When looking at a star, it will appear over the cross-hair.

Time Measurements
The Approximation Of Minecraft Time to Real Time


 * 1 Minecraft Year is ≈ 120 Hours of gameplay. ( 10 + 7 + 1.5 + 1.5 ) * 365 / 60 = 120
 * 1 Minecraft Month is ≈ 10 Hours of gameplay. ( 10 + 7 + 1.5 + 1.5 ) * 30 / 60 = 10
 * 1 Minecraft Week is ≈ 2.333 Hours of gameplay. ( 10 + 7 +  1.5 + 1.5 ) * 7 / 60 = 2.333
 * 1 Minecraft Day is = 20 Minutes of gameplay. 10 + 7 + ( 1.5 + 1.5 ) = 20

The Approximation Of Real Time to Minecraft Time


 * 1 Real Day of gameplay is = 72 Minecraft Days. 24 * 60 / 20 = 72

''Note: Real time is the time spent playing minecraft.