About
A small tool for people who chase light.
sunhour computes the times of sunrise, sunset, golden hour, blue hour, civil/nautical/astronomical twilight, solar noon, day length, and the moon's phase for any place on Earth — for today, tomorrow, this week and this month.
Who it's for
The same numbers matter to a lot of different people:
- Photographers planning around the warm, low-angle light of golden hour and the cool blue glow that follows it.
- Hikers and climbers who need to be off a ridge before dark and want to know how long they have.
- Surfers, sailors, anglers reading the light and tide-adjacent rhythms of a day.
- Religious users for whom dawn and dusk define the day's structure of prayer and fasting.
- Astronomers and stargazers looking for the end of astronomical twilight — the moment "real" night begins.
How the math works
Solar positions come from the NOAA Solar Position Algorithm — the same equations the National Oceanic and Atmospheric Administration publishes for the U.S. government. They're accurate to about one minute for any year between 1900 and 2100, and at any latitude up to the polar circles. Past those, where the sun stops rising or setting for parts of the year, the tool correctly reports "no event".
Moon phase uses the standard Conway approximation — accurate to within a day, which is plenty for displaying a named phase ("Waxing Gibbous") and an illumination percentage. Moonrise and moonset are computed by sampling the moon's altitude every ten minutes through the day and finding when it crosses the horizon.
What it doesn't do — yet
For now: no historic dates, no future years, no offline mode, no public API. If the tool gets useful, those land in version 2. For comments, ideas, or "you're wrong, the sunset in Reykjavik is actually two minutes off" emails, write to [email protected].
Credits
Built with Laravel, Tailwind CSS, and Alpine.js. Typography by Fraunces (display) and Inter (body). The horizon gradient is hand-tuned to match the actual sky colors at each twilight stage.