About LightOtter

What LightOtter is

LightOtter is a small morning sunlight app with Ollie the otter. Every morning it estimates how many minutes of outdoor daylight to aim for and turns that into a daily mission with a timer and a streak.

How the rule of thumb works

The base comes from cloud cover: 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, and the result stays between 6 and 30 minutes. Weather data comes from Open-Meteo; the sun position is calculated on your device.

What LightOtter is not

LightOtter is not medical advice and not a medical device. The minutes are a rule of thumb, not a measurement. If you feel tired for a long time, talk to a doctor. Never look directly at the sun.

Who is behind it

LightOtter is an independent app from Germany. Details about the provider are in the imprint.

Contact: hello@lightotter.com

Try the morning light calculator · Imprint

Sources

  1. 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.
  2. 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.

Last reviewed: October 2026