Tukuk-OS🌅 Sunrise & Sunset
Any place · any date · almanac math computed from arithmetic, not an API
Sunrise & Sunset for any place on Earth and any date: when the sun actually crosses the horizon, when solar noon falls, how long the day lasts, and when civil twilight begins and ends. The arithmetic runs on our own server from the textbook solar-position algorithm — no API can be down, rate-limited or sold — and it matches printed almanacs to within a minute or two.
Why solar noon is not 12:00
Every clock rounds the Sun’s behaviour to a tidy time zone, but the Sun does not negotiate. True solar noon — when the sun due south (or north) climbs highest — drifts up to about 15 minutes back and forth all year from the equation of time (Earth’s tilted, slightly squashed orbit), and then by up to a full hour or more from your time zone’s political width. That is why the noon row here rarely reads 12:00, and why the time zone guide is worth your five minutes.
What the numbers include
Sunrise and sunset are the moment’s upper edge of the sun touching the horizon, with air refraction built in (the atmosphere bends light about half a degree, lengthening every day on Earth by a handful of minutes). Civil twilight marks the sun 6° below the horizon — the usual line between “daylight enough to read outside” and not. Inside the Arctic and Antarctic circles the sun may never rise or never set, and the page says exactly that instead of inventing a time. On reading the clock rows: the big figure is UTC — universal, unambiguous — and the small one is the nearest standard meridian estimate, which can differ from the political clock by an hour or two. Related: latitude & longitude, distance calculator, maps & navigation.