Waiting

Waiting is an action in Fallout 3, Fallout: New Vegas and Fallout 4. It can be used to advance the in-game clock by a selected number of hours in only a few moments of real time. Waiting is useful for accessing stores or buildings that only open at a specific time, hastening some NPCs to your location or some other designated location, and allowing the sun to come up (or go down) before advancing to a new destination.

You can also open up the waiting menu by interacting with a bed that is not considered owned by another NPC, although this will trigger Resting instead. Resting is functionally similar to waiting, but it also restores Health and may confer other temporary status benefits, such as Well Rested.

In certain circumstances, there may be times when you are unable to wait. You cannot wait while enemies are nearby, when trespassing, while jumping or falling, while swimming, while being irradiated, or during dialog. These restrictions also apply to resting.

Fallout 3 and Fallout: New Vegas
It is done by pressing the "Select" button on the PlayStation 3, the "Back" button on the Xbox 360 and the "T" button (by default) for the PC.

Fallout 4
To wait, the Sole Survivor must first sit down on a chair, couch or bench. If you are allowed to wait at that time, the game will then indicate what button to press to wait at the bottom of the screen.

Bugs

 * If you wait while you're addicted or sleep deprived, the screen may turn black for 10-15 seconds after the waiting time has finished.
 * If your controller disconnects on a 24 hour waiting session the arrow will still go. If the waits ends with controller disconnected the game may freeze.
 * If you press the home button, immediately after starting the countdown, The wait time will speed up significantly. This is useful for long waiting sessions and will also work in Skyrim.
 * As soon as the countdown starts on the wait screen, if the player presses the directional button to wait an extra hour, it will immediately go forward then back allowing a free hour in Hardcore mode without any ill effects such as the dehydration that would have happened by actually waiting or playing that extra hour.
 * When you adjust and confirm the timer to wait longer than 4 hours, sometimes the clock will only go forward by one hour instead of the suggested time. If you try waiting again, the timer will correct itself and wait for the desired time.