Pick a date to compare, or read the yearly table to see the solstices at a glance.
How sunrise and sunset are calculated
The times of sunrise and sunset depend on three things: your latitude, your longitude and the sun’s position in its yearly path, called its declination. SunriseKit uses the standard astronomical formulas behind almanac tables. It finds the moment of solar noon, when the sun is highest, and then the moments before and after when the sun’s centre is 0.833° below the horizon. That small angle allows for the sun’s radius and for atmospheric refraction, which bends light so that we see the sun slightly before it is geometrically above the horizon. The same method with other angles gives the golden hour, blue hour and twilight times.
Why times change through the year
Because the Earth’s axis is tilted by about 23.4°, the sun climbs higher and stays up longer in summer. Near the equator the effect is small and days stay close to twelve hours. At 50° north, as in London or Vancouver, the longest day is more than sixteen hours and the shortest about eight. Above the Arctic Circle the sun can stay up all day in June and never rise in December. The earliest sunset and latest sunrise do not fall exactly on the solstice: the Earth’s elliptical orbit shifts solar noon by up to sixteen minutes during the year, which is why the earliest sunsets come in early December and the latest sunrises in early January.
Golden hour, blue hour and twilight
Photographers prize the golden hour, when the sun is low and light is warm, soft and long-shadowed, and the blue hour that follows sunset or precedes sunrise, when the sky glows deep blue and city lights balance with the sky. Civil twilight is the period when there is enough light for most outdoor activities without lamps. Nautical twilight is when the horizon at sea is still visible for navigation. Astronomical twilight ends when the sky is fully dark and faint stars and galaxies can be seen.
Local conditions
Calculated times assume a flat horizon at sea level. Mountains, tall buildings and trees can hide the sun for longer, while standing on a high point lets you see it a little earlier. Unusual temperatures can also change refraction by a minute or so. Your chosen place and coordinates are saved only in this browser.
Frequently asked questions
When is the shortest day?
Around December 21 in the northern hemisphere and June 21 in the southern hemisphere.
Is day length 12 hours at the equinox?
Slightly more, because refraction and the sun’s size add a few minutes.
What is midnight sun?
Above the Arctic Circle in summer the sun stays up all day; the calculator shows this.
Is SunriseKit free?
Yes, with no sign-up or ads.
Is my location stored?
Only in this browser. Nothing is sent to a server.