In Tomodachi Collection, the environment changes gradually throughout the day. In Tomodachi Life, however, once a certain time is reached, the environment will change with a one-second transition to the matching time of day. The same will happen if you set your 3DS to Sleep Mode for a few minutes until a certain time is reached.
There are four preset times of the day. 6:50 AM to 8:25 AM is Early Morning, where the sky will be a very light blue, and most Miis will still be asleep. A rooster can be heard during this time. 8:25 AM to 4:10 PM is Daytime, where the sky is a darker blue, and all Miis are awake. 4:10 PM to 6:10 PM is Evening, where the sky becomes red-orange and a crow can be heard. And 6:10 PM to 6:50 AM is Night, where the sky will be very dark blue, almost purple. After a certain amount of time, an owl can be heard. Miis will start to fall asleep at around 9:30 PM. Here's a table to organize all of that information.
| Time of Day | Time | Sky Color | Animal heard during this time |
|---|---|---|---|
| Early Morning | 6:50 AM - 8:25 AM | Light Blue | Rooster |
| Daytime | 8:25 AM - 4:10 PM | Blue | none |
| Evening | 4:10 PM - 6:10 PM | Orange | Crow |
| Night | 6:10 PM - 6:50 AM | Purple | Owl |
In Tomodachi Collection, the environment changes gradually instead of there being four preset environments, but we do know that Night ends at 6:40 AM.