CircadiaOSThe schedule
Your body temperature drops as you fall asleep and rises before you wake. A flat thermostat ignores that. CircadiaOS sends a four-phase curve to your thermostat every evening:
Pre-sleepEarly nightLate nightPre-wake
| Phase | When | What it does |
|---|---|---|
| Pre-sleep | ~45 min before bed | Starts cooling the room so it is already cooler when you get into bed. |
| Early night | First half | Coldest point, aligned with deep sleep. |
| Late night | Second half | Slight rise so you don't overcool. |
| Pre-wake | Before your alarm | Warmest point, matching your natural morning rise. |
The schedule is sent before bed and runs on its own. CircadiaOS doesn't adjust your thermostat in real time — wearables only report sleep data the next morning. Every decision is made between nights, from complete data.
How it learns
On Premium, CircadiaOS dials in your schedule in two phases:
- The first 14 nights. Your schedule runs unchanged while CircadiaOS records how you sleep on it. The median becomes your starting point.
- One change at a time. It adjusts a single setpoint, holds it for 1--2 weeks, and reads your sleep against that starting point. Over time, CircadiaOS finds what works for you.
You set your own temperature floor and ceiling, and CircadiaOS stays inside them. You can override the thermostat by hand any time — CircadiaOS picks back up the next night.
Related guides
- Best temperature for sleep — the research and the overnight curve.
- Why do I wake up at 3am? — how the late-night warming phase prevents early wake-ups.
- Connect Oura to your thermostat — close the loop between your wearable and your room.
- Apple Watch + thermostat — use your Apple Watch sleep data to drive your thermostat.
- Smart thermostat sleep schedule — how to program a four-phase overnight schedule by hand.
- Compatibility — supported thermostats and wearables.
- Setup guide — what you need and how to get started in five minutes.