How much morning sunlight do you need?
Check today’s number: enter your city or use your location. LightOtter looks at the clouds and the height of the sun and gives you a rule-of-thumb estimate of minutes outside.
How much daylight is in your day? Take the light check (1 minute)
Weather data by Open-Meteo.com (CC BY 4.0). Location data based on GeoNames.
The short answer
As a rule of thumb, aim for about 10 minutes of outdoor light on a clear morning, 15 minutes when it is partly cloudy and 20 to 25 minutes when it is overcast. With a very low sun it can be up to 30 minutes. It is an estimate for a daily routine, not a measurement.
| Sky in the morning | Minutes outside |
|---|---|
| Clear or sunny | about 10 |
| Partly cloudy | about 15 |
| Overcast | 20 to 25 |
| Low sun or dark season | up to 30 |
Not a tanning or sunbathing guide
These minutes are about daylight for your daily rhythm, not about sunbathing or getting a tan. How much sun your skin can take depends on the UV index, your skin and the season. When the UV index is 3 or higher, the WHO recommends sun protection – shade, clothing, a hat and sunscreen.
Why outside beats the window
A window lets in plenty of light, but indoors you only see a small part of the sky. Even under clouds, the sky outside is usually many times brighter than a lit room, and direct sun is brighter still; the exact values vary a lot with weather and season. That is why a short walk usually gets you far more light than an hour at the desk by the window.
Just be outside; you never need to look up at the sky, and never look directly at the sun.
Dark winter mornings
In the dark months the sun may rise after you get up. The calculator then shows your first daylight window after sunrise. You can fit it into the way to work, a school run or a first break. Until it is light, bright light indoors can make the wait easier; if you use a daylight lamp, follow its instructions.
What research says
An international expert panel has published recommendations for how much light people should get during the day, in the evening and at night, together with a standard way to measure it (Brown et al., 2022).
In a camping study, people living with electric light got less sunlight during the day, more light after sunset and had a later body clock than under natural light only. After living with natural light, their internal clock lined up with sunrise and sunset (Wright et al., 2013).
LightOtter’s minutes are not taken from these papers. They are a simple rule of thumb that turns clouds and sun height into a habit you can keep every morning.
- Circadian rhythm
- Winter tiredness
- Reset your circadian rhythm
- Social jet lag
- Daylight saving time
- Sleep schedule in one day?
- Become a morning person
- Morning routine
- Early bird or night owl
- Morning walk
- Sunlight through a window
- How bright is daylight?
- Jet lag and light
- Apple Watch Time in Daylight
- Huberman and morning sunlight
- Night routine
- Shortest day of the year
- Bear, wolf, lion, dolphin
- When the clocks go back
- Lux meter app
- Shift work and light
Morning daylight by city and month: the table for 11 cities
How the estimate works
- Clouds set the base: about 10 minutes when it is clear, 15 when it is partly cloudy and 20 to 25 when it is overcast.
- The sun’s height adjusts it: a low morning sun adds time, a high sun takes a little off.
- The result stays between 6 and 30 minutes. It is a rule of thumb for a daily routine, not a measurement.
Questions about the calculator
How long should you get morning sunlight?
There is no single number that fits everyone (Piper et al., 2026). As a rule of thumb, LightOtter aims for about 10 minutes outside on a clear morning, 15 when it is partly cloudy and 20 to 25 when it is overcast, up to 30 with a low sun.
Why does the number change with the weather?
Clouds and a low sun make daylight dimmer, so you need a little longer outside to get a similar amount of light.
Does the calculator store my location?
No. Your browser rounds your coordinates to about 10 km (6 miles) before they are sent, and they are only used to fetch the weather. LightOtter does not store your location.
Sources
- Brown, T. M., 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.
- Wright, K. P., Jr., et al. (2013). Entrainment of the human circadian clock to the natural light-dark cycle. Current Biology 23(16): 1554–1558.
- Piper et al. (2026). Bright days, dark nights (policy brief). Public Health Reviews 47.
- World Health Organization (2002). Global Solar UV Index: A Practical Guide.
Last reviewed: October 2026