Time change is a feature from Super Smash Bros. Brawl onward where some stages and areas depict various transitions in time over the course of a match. All effects are purely aesthetic and have no impact on gameplay.
The extent of transformation depends on the stage. Some stages show rapid changes in time, while others change in response to the console's internal clock when the match is started. Three time changes also take place in real-time, with replays of these saved matches featuring the time based on when the replay is played back.
List of stages with time changes
All-Star Rest Area (SSB4)
Super Smash Bros. 4's All-Star Rest Area is unusual amongst time-changing stages in that it does not change while the player is in it. Instead, the stage progresses from dawn to dusk as the All-Star Mode is progressed through.
Battlefield features a day to night cycle. A sundial behind the playable area shows the time of day as well. The cycle lasts three minutes.
This stage has a daily cycle, like Brawl Battlefield, on both the Wii U and 3DS versions of the game. The cycle lasts two minutes.
While Ultimate's iteration of Battlefield does not feature a day-night cycle, it instead features a periodically occurring solar eclipse to similar effect, causing the background to darken briefly before lightening up again.
In both Brawl and Smash 4, if the Sandbag is hit far enough, the time will change from day to evening, and then night. If hit even farther, it will change from night to day again.
Prism Tower's time change aspects are linked to the where the fight is taking place. At the ground level of Lumiose City, the stage takes place in the day; as the stage begins to go higher up Prism Tower time passes, and at the apex the stage turns to night, returning to dawn during the descent to its initial form.
Like the Animal Crossing games, Smashville's time changes are based on the actual system clock; the variation is based on the current time when the stage is loaded, and unlike the Animal Crossing games, it does not change in real time. The system clock also determines what time shows up on the clock of the Town Hall building. True to the source, K.K. Slider appears and holds a concert on Saturdays between 8:00 PM and 12:00 AM.
Like Smashville, the time of day changes on this stage depending on the system clock, using the same mechanics. The clock on the Happy Room Academy building during the city phase of the background transition also matches the system clock. K.K. Slider still performs concerts on Saturday nights.
In Super Smash Bros. 4 and Super Smash Bros. Ultimate, the face of the falling clock tower face matches the system's internal clock. It is even possible to see the clock hands moving. If the game is paused, the clock stops moving; when the game is un-paused, the clock skips ahead and resumes moving from the time at which the game was un-paused.
This stage uniquely features a seasonal cycle, with each season lasting about 30 seconds. The song Obstacle Course syncs to the different seasons, with one variant playing in Autumn and Winter, and another playing during Spring and Summer.