About this tool
This sunrise and sunset calculator gives the times the Sun rises and sets at any point on Earth on any date, along with solar noon, the length of the day, and the start and end of civil, nautical, and astronomical twilight. Pick a city from the preset list, type a latitude and longitude, or use your device's location; then choose the date and the time zone the results should be displayed in. A 24-hour bar shows how the day divides into night, the three twilight bands, and daylight, and a 12-month table shows how sunrise, sunset, and day length shift across the year at that spot. It is useful for photographers planning golden hour and blue hour, hikers and sailors checking usable light, anyone timing a run or a commute around daylight, and teachers or students exploring how latitude and season change the length of the day, including the polar day and polar night above the Arctic and Antarctic circles.
How it works
Times come from the NOAA Solar Calculator equations (based on Jean Meeus's Astronomical Algorithms). For the chosen date the calculator forms the Julian day, then the Julian century T, and from T the Sun's geometric mean longitude and mean anomaly, the eccentricity of Earth's orbit, the equation of center, the true and apparent longitude, and the mean obliquity of the ecliptic corrected for nutation. Those give the Sun's declination and the equation of time. Solar noon in minutes UTC is 720 − 4·longitude − equation of time. The hour angle at sunrise is acos(cos(zenith) ÷ (cos φ · cos δ) − tan φ · tan δ) with φ the latitude, δ the declination, and a zenith of 90.833° (the geometric horizon plus 34′ of atmospheric refraction plus the Sun's 16′ semi-diameter). Sunrise is solar noon minus 4 minutes per degree of hour angle and sunset is solar noon plus the same; the calculator recomputes the declination and equation of time at the first-pass event time and evaluates once more for a result within about a minute of published almanacs. Civil, nautical, and astronomical twilight use zeniths of 96°, 102°, and 108°. If the cosine of the hour angle falls outside −1…1 the Sun never crosses that zenith on that date, which is reported as polar day or polar night. All instants are computed in UTC and then formatted in the selected IANA time zone with the browser's Intl library, so daylight saving time is handled automatically.
Frequently asked questions
How accurate are the sunrise and sunset times?
For latitudes below about 60° the NOAA algorithm agrees with the US Naval Observatory tables to within a minute or so. Actual atmospheric refraction varies with temperature and pressure, which can shift the real moment by a minute or two, and near the poles, where the Sun skims the horizon at a shallow angle, small refraction differences can move sunrise by ten minutes or more. Times also assume a flat sea-level horizon: mountains, buildings, or altitude change what you see.
What is the difference between civil, nautical, and astronomical twilight?
They are defined by how far the Sun's center is below the horizon. Civil twilight (0° to 6° below) is bright enough for most outdoor activity without artificial light; it is the usual legal definition of dusk and dawn for headlights and aviation. Nautical twilight (6° to 12°) is when the horizon is still visible against the sky, so sailors could take star sights. Astronomical twilight (12° to 18°) is when the sky is still faintly lit; after it ends the sky is fully dark for astronomy.
Why is solar noon not at 12:00?
Clock time is tied to a time zone's central meridian, but the Sun is highest when it crosses your own meridian, so every degree of longitude you are west of the zone's reference shifts solar noon four minutes later. On top of that the equation of time, caused by Earth's tilted axis and elliptical orbit, moves solar noon up to 16 minutes earlier or later through the year, and daylight saving time adds another hour. Solar noon at 13:00 or later in summer is normal.
What does polar day or polar night mean in the results?
Above roughly 66.5° north or south there are dates when the Sun never sets (polar day, or midnight sun) or never rises (polar night). The calculator detects this when the hour angle equation has no solution and shows the status instead of a time. Twilight bands can still occur in polar night, so you may see civil dawn and dusk times while sunrise and sunset are marked as not occurring.