Calibrate

Morning light planner

When to step outside in the morning and for how long, from your city's real sunrise and the time you wake. No signup needed.

Sunrise comes from your city's position and time zone. Cities over 100,000 people are listed, plus smaller cities in the far north and south.

I wake up at

Drag or scroll to adjust. Tap the time to type.

The sky that morning

Enter your wake time and a date to see your morning light window.

Morning light is the first move of the day

Calibrate builds a daily plan around your wake time: when to get light, when to stop caffeine, and when to dim the lights at night.

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Related reads: How much morning sunlight you need and Light therapy lamps: how to choose one.

How long should you get morning sunlight?

When

The first hour after you wake

Sunny morning

10 to 15 minutes outside

Cloudy morning

20 to 30 minutes outside

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Morning light, soon after you wake, is the main thing that keeps your body clock on time. When Wright and colleagues took people camping, a week of natural light moved their body clocks about two hours earlier 1. The planner takes your wake time and your city's sunrise for the date you pick and marks the first waking hour that has daylight in it.

If the sun rises an hour or more after you wake, the window starts at sunrise instead and runs for half an hour. Until then, the brightest lights you have are the next best thing.

Why outside beats a bright room

Your eyes adjust so well that a lit room feels bright, but most rooms are only a few hundred lux. Outdoors, an overcast morning still gives several thousand. A 2022 expert panel recommended daytime light at eye level of at least 250 lux melanopic EDI, a level outdoor light reaches even on a gray day and most rooms do not 2.

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Winter is no reason to stay in. When the camping study was repeated in winter, people's body clocks still moved earlier outdoors 3. Go out anyway and stay closer to 30 minutes.

Before sunrise, in winter, or indoors

The morning sunlight guide covers what to do when you wake in the dark, what to do if you can only get light through a window, and how a light box can fill the gap on dark mornings. If you are trying to move your whole schedule earlier, the sleep schedule guide takes it step by step.

Morning sunlight FAQ

How long should you get morning sunlight?

As a rule of thumb, 10 to 30 minutes outside in the first hour after waking. Closer to 10 to 15 minutes on a clear, bright morning, and closer to 20 to 30 when it is overcast or the winter sun is low. Nobody knows the minimum for healthy adults, partly because people differ so much in how sensitive they are to light.

What time should you get morning sunlight?

Soon after you wake, ideally within the first hour. Light then has the biggest effect on keeping your body clock on time. The planner uses your wake time and your city's sunrise to show that window for a given date.

What if I wake up before sunrise?

Turn on the brightest lights you have while you get ready, then step outside once it is light, even briefly. If the sun is up within your first waking hour, the planner starts your window at sunrise.

Does morning light count on a cloudy day?

Yes. An overcast morning outdoors still gives several thousand lux, far more than most rooms, so go out anyway and stay closer to 30 minutes. When researchers repeated a camping study in winter, people's body clocks still moved earlier outdoors.

Does morning light through a window work?

Less well than going outside. Light drops off quickly as you move back into a room, and tinted glass cuts it further. If a window is all you have, sit right next to the brightest one, facing it, with the blinds fully open.

References

  1. Wright KP Jr, McHill AW, Birks BR, et al. (2013). Entrainment of the human circadian clock to the natural light-dark cycle. Current Biology, 23(16), 1554-1558. doi.org/10.1016/j.cub.2013.06.039
  2. Brown TM, Brainard GC, Cajochen C, et al. (2022). Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults. PLOS Biology, 20(3), e3001571. doi.org/10.1371/journal.pbio.3001571
  3. Stothard ER, McHill AW, Depner CM, et al. (2017). Circadian entrainment to the natural light-dark cycle across seasons and the weekend. Current Biology, 27(4), 508-513. doi.org/10.1016/j.cub.2016.12.041

This planner is for wellness education, not medical advice. Do not look straight at the sun. If you have an eye condition or take light-sensitizing medication, ask a clinician before making big changes to your light exposure.

Morning Light Planner: When to Get Sunlight | Calibrate