Sunrise and sunset times and daylight planner

This daylight planner gives sunrise and sunset times, civil dawn and dusk, and day length for any place and date. It then lines those up with your wake time and bedtime: get outdoor light in the first hour after waking, dim your lights for the 3 hours before bed, and keep the bedroom dark overnight.

How the sunrise and sunset times are calculated

The planner uses the solar position equations published by NOAA's Global Monitoring Laboratory, which are based on Jean Meeus's Astronomical Algorithms. NOAA states the method is accurate to within a minute for places between 72° north and south, and within 10 minutes nearer the poles.¹ Sunrise and sunset include NOAA's 0.833° allowance for the air bending sunlight near the horizon. Civil dawn and dusk are when the sun is 6° below the horizon.²

For every city in the list below the Arctic Circle, the code matches NOAA's own calculator code to within a minute across 2026. Above the Arctic Circle you will see "no sunrise" in midwinter and "sun up all day" in midsummer. The timeline still shows civil twilight, which is often the only natural light on polar-night days.

Everything runs in your browser. "Use my location" asks your browser for coordinates, rounds them to two decimals (about 1 km) and does not send them anywhere.

Why the morning sunlight window starts when you wake

The body clock responds to light differently depending on when it arrives. In a lab study of 18 adults, a single hour of light at about 8,000 lux moved the clock later when it came in the evening and early night, and earlier when it came in the late night and early morning, timed against each person's melatonin rhythm. The largest raw shifts were about 1.2 hours earlier and 2 hours later.³

Outdoor light is much brighter than indoor light. In a small winter camping study (n=5), people got over 13 times more light than at home, about 10,300 lux on average against 750 lux, and their evening melatonin rise came about 2.6 hours earlier.⁴

The planner marks the first hour after your usual wake time. That hour is a practical target, not a number from a trial. If the sun rises after the window ends, it tells you so: turn on bright indoor light when you wake, or use a light therapy lamp, then get outside once it is up. A sunrise alarm clock is a gentler way to wake before dawn.

Where the evening and night light limits come from

In 2022 a group of circadian and sleep researchers published light recommendations for healthy adults aged 18 to 55 in PLOS Biology.⁵ They are given in melanopic equivalent daylight illuminance (melanopic EDI), measured at the eye in the vertical plane, about 1.2 m up:

• Daytime: at least 250 melanopic lux, using daylight first where possible.
• Evening, starting at least 3 hours before bedtime: 10 melanopic lux or less.
• Sleep: 1 melanopic lux or less. If you need light at night, 10 or less.

Melanopic lux weights light by how strongly it drives the melanopsin cells in the eye that signal to the body clock. An ordinary lux meter or phone app reads photopic lux, which is not the same number. Warm light with less short-wavelength content gives fewer melanopic lux for the same brightness, which is why the paper suggests it for evenings. See how many lux you need and light meters if you want to measure.

Assumptions and limits

• Times are shown in your device's time zone. If you pick a city in another zone, the times are converted to your clock, not the city's.
• Weather, shade, buildings, hills and elevation are ignored.
• The light targets are for healthy adults on a regular schedule. Crossing time zones calls for different timing: use the jet lag planner. Night workers should see shift work sleep.
• This is general information, not medical advice. If you have bipolar disorder, an eye condition, or take medicines that make you sensitive to light, talk to a doctor before using a bright light lamp.

Sources

1. NOAA Global Monitoring Laboratory. Solar calculation details. gml.noaa.gov/grad/solcalc/calcdetails.html
2. NOAA Global Monitoring Laboratory. Solar calculator glossary. gml.noaa.gov/grad/solcalc/glossary.html
3. St Hilaire MA, Gooley JJ, Khalsa SBS, Kronauer RE, Czeisler CA, Lockley SW. Human phase response curve to a 1 h pulse of bright white light. J Physiol. 2012;590(13):3035–3045. doi:10.1113/jphysiol.2012.227892
4. Stothard ER, McHill AW, Depner CM, et al. Circadian entrainment to the natural light-dark cycle across seasons and the weekend. Curr Biol. 2017;27(4):508–513. doi:10.1016/j.cub.2016.12.041
5. Brown TM, Brainard GC, Cajochen C, et al. Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults. PLOS Biol. 2022;20(3):e3001571. doi:10.1371/journal.pbio.3001571