Cycles

This article has not been revised for the current version (***U50-582745***). It was last updated for *an unknown version*. It may contain inaccuracies.
This article has not been revised for the current version (***U50-582745***). It was last updated for *an unknown version*. It may contain inaccuracies.

**Cycles** are the term used for the day/night cycle in Oxygen Not Included. One cycle lasts 600 seconds in total, with 525 seconds of daytime and 75 seconds of nighttime. The slowly rotating asteroid image in the top left of the UI represents the clock.

## Daytime

The brighter side of the asteroid represents daytime. Duplicants will usually perform jobs and other actions during daytime.

The sun shining on the Asteroid starts with dawn at 0 Lux, decelerating the closer it gets to midday and 79.999 Lux and past midday accelerates the closer it gets to 0 Lux, reaching it when Nighttime starts.

## Night-time

The darker side of the asteroid represents nighttime and is when Duplicants will usually go to sleep. Red alert prevents Duplicants from sleeping.

Hatches are night active creatures and will look for food. At the end of the night they will try to find some natural tile to dig in.

During night-time, a Duplicant with the Night Owl trait will find most of their skills increase by 3.

No sun shines on the asteroid during nighttime, Solar Panels will not work.

### Sleep

Sleeping restores Duplicant's stamina. Duplicants do not need a full night sleep to restore full stamina. Hunger, light and full bladder cause "interrupted sleep". Flatulent and Loud Sleeper Duplicants can wake others up, too. Sleep interruption annoys Duplicants during the following daytime and adds to their Stress, in addition if their stamina runs out during the work-shift they might fall asleep right on the spot, interrupting their duties and receiving all relevant morale penalties.

## Schedule

In the "Schedule" menu one can see the current Schedule of each Duplicant and modify it, add and delete new Schedules, rename Schedules, toggle sound notifications and move Duplicants to Schedules by clicking on the arrow.

There are 24 blocks with each block representing 25 seconds. Those can be switched to Bathtime, Work, Downtime and Bedtime.

The Default Schedule is 1 Block of Bathtime, starting at dawn, followed by 18 blocks of Work and 2 Blocks of Downtime are scheduled before the 3 Blocks of Bedtime.

* During **Work**, Duplicants will focus on accomplishing their tasks, only eating and using the bathroom when absolutely necessary.

* During **Bathtime**, Duplicants will prioritize Bathroom activities at >40% Bladder and work otherwise.
Duplicants will need to use bathroom at least once per cycle. If bathtime/downtime is spaced out by 10 blocks it will increase to two times. Since sanitary buildings are communal, Bathtime is the prime candidate for splitting schedules to normalize peak load.

* During **Downtime**, Duplicants will prioritize visiting the bathroom (>40% Bladder), eating (when below 3300 kcal) and leisure activities. Each bonus Downtime slot besides the first one increases Morale by 1, up to +4. If the duplicant isn't hungry, has an empty bladder, has no recreation tasks and has no recreation room or Printing Pod to idle by, the duplicant will choose to work during their downtime.

* During **Bedtime**, Duplicants will sleep and nothing else matters, unless it is really really important. Namely only because of a bursting Bladder, low Oxygen or due to Starvation (less than 1000 kcal) they will get up.
Duplicants normally lose only 70% of stamina per cycle and recover 38.75-42.9% per block while sleeping in a cot (~43-51% in a Comfy Bed), and the Barracks or Bedroom rooms further speed up the stamina recovery.
If a duplicant hasn't reached 100% stamina by the end of Bedtime, they will continue sleeping until they reach 100% stamina through Work and Bathtime blocks, but not Downtime. So with a short Bedtime and Work or Bathtime after sleeping, as long as duplicants reach their bed by the end of Bedtime, they will continue sleeping and only wake up once stamina has recovered to 100%.

The Schedule can be free adjusted to deal with Loud Sleepers, Night Owls, Early Birds, objects with limited interaction slots, too limited downtime to do everything needed, less than three blocks being needed for sleep and hunting for Hatches.

### Early Bird and Night Owl

* During 3 rightmost blocks duplicants with Night Owl trait gain +3 to all attributes.
* During 5 leftmost blocks duplicants with Early Bird gain +2 to all attributes.
* The bonus productivity time can be lost while traveling to and from bedrooms, so it may help to buffer these schedules with an additional work block on either side.

## Timings

The whole day in Oxygen Not Included lasts 10 minutes (600 seconds) at normal speed, with 1 minute and 15 seconds being nighttime.

From experiments with batteries, power consumers and timer sensors, the game engine appears to evaluate 5 ticks per second.

Speed controls switches are 1x, 2x, and 3x speed, and debug super-speed value is 10x.

## Achievements

There are two cycle-based Achievements:

* Turn of the century: Unlocked at cycle 100
* One Year, to be Exact: Unlocked at cycle 365.25

Some other achievements have cycles as one criterion, e.g. for the *Home Sweet Home* achievement, at least 200 cycles need to pass, while the *Carnivore* achievement needs to be reached before the 100th cycle.