Sunrise & Sunset Calculator

A perfectly geometric 90 degrees would mark the instant the sun's center crosses the true, airless horizon — but two real-world effects push the visible event later at sunrise and earlier at sunset. Atmospheric refraction bends light near the horizon, lifting the sun's apparent position by about 34 arcminutes, and the sun isn't a point: its disc has an apparent radius of about 16 arcminutes, so "sunrise" is defined as the moment the top edge of the disc appears, not its center. Add those two corrections (34' + 16' = 50', or 0.833 degrees) to 90 degrees and you get 90.833 degrees — the standard convention used by NOAA, the US Naval Observatory, and this calculator.

Civil twilight has one fixed, official definition: it ends (in the evening) or begins (in the morning) when the sun's center is 6 degrees below the horizon — roughly the point where there's still enough skylight to make out shapes outdoors without artificial light. Golden hour has no single official definition; it's a photography convention for the warm, low, soft light that happens while the sun sits at a low angle. This calculator approximates it as the sun's elevation being between +6 degrees and -4 degrees, which is why the golden hour window straddles sunrise and sunset rather than starting exactly at either one.

Two separate effects push it off. First, the equation of time: Earth's elliptical orbit and axial tilt mean the sun doesn't cross your meridian at a perfectly even 24-hour interval every day, so true solar noon drifts up to about 16 minutes early or late across the year relative to mean (clock) time. Second, civil time zones are wide, roughly 15 degrees of longitude each, but the sun only cares about your exact longitude — stand near the eastern edge of your zone and solar noon happens earlier by the clock; stand near the western edge and it happens later. Daylight saving time adds a further flat one-hour shift on top of both.

Both come from the same hour-angle equation this calculator solves for sunrise and sunset having no real solution on a given day. Near the Arctic and Antarctic Circles (about 66.5 degrees latitude) and beyond, the combination of your latitude and the sun's declination on that date can put the sun's daily circle entirely above the horizon ("midnight sun", commonly in local summer) or entirely below it ("polar night", in local winter). The closer you are to a pole, the longer these all-day/all-night stretches last — right at the poles they each run about half the year.

For the 20 preset cities, this calculator knows the exact IANA time zone (e.g. America/New_York) and hands it to the browser's built-in Intl API, which correctly applies daylight saving rules for that specific date — no guesswork. For manual coordinates or your GPS location, there's no offline database mapping arbitrary latitude/longitude to a civil time zone boundary (that data is large and changes with local law), so the calculator instead estimates a fixed UTC offset from longitude alone (15 degrees per hour) and labels it clearly as an estimate with no daylight-saving adjustment. If you need an exact clock time for a real place, picking the nearest preset city gives you that.

The underlying NOAA solar-position equations are accurate to well within a minute for the sun's geometric position almost everywhere on Earth, which is the same math behind most sunrise/sunset almanacs. What it can't account for is your specific horizon: a mountain ridge, a tall skyline, or being down in a valley will delay the sun's appearance or hide it earlier than the flat-horizon time shown here, sometimes by many minutes. Treat the numbers as a very close planning estimate, and for safety-critical use (maritime, aviation, religious observance with strict timing rules) confirm against your local official almanac.