Set day
Switch to daytime with the /time set day command and get rid of the night.
Commands
/time set day Sets early morning (1,000 ticks)
/time set noon Sets noon (6,000 ticks)
/time set 0 Sets sunrise (0 ticks)
/gamerule doDaylightCycle false Stops the day/night cycle
How it works
A full day/night cycle in Minecraft lasts 20 minutes (24,000 ticks). Day starts at 0 (sunrise) and lasts until 12,000 (sunset), and night runs from 13,000 to 23,000. The /time set day command sets the time to 1,000 ticks: early morning in full sunlight. Alternatively, /time set 6000 sets noon, the brightest moment of the day. Changing the time affects many game mechanics: zombies and skeletons burn in sunlight, villagers get up and go back to work, and bees leave their hives. The /gamerule doDaylightCycle false command stops time, which is handy when you want endless daytime. On multiplayer servers, changing the time affects all players at once, because time is shared across the whole Overworld. The Nether and the End have a fixed time, so time commands make no visible difference there.
Practical tips
A value of 1,000 is morning, 6,000 is noon and 12,000 is sunset.
/gamerule doDaylightCycle false freezes time, which is perfect for building.
Time only applies to the Overworld: the Nether and the End have a fixed time.
Zombies and skeletons burn during the day unless they're wearing a helmet.
