Sunrise, Sunset and When It Gets Dark

What time does it get dark?

Sunset isn't the moment it gets dark. After the sun drops below the horizon, the sky stays bright for a while because sunlight still reaches the upper atmosphere and scatters down to you. Astronomers split this twilight into three stages by how far the sun is below the horizon: civil (down to 6°), nautical (12°) and astronomical (18°).^[46] The time we show as "dark at" is the end of civil twilight, the point after which you'd normally need a light to be outdoors. Truly dark skies, good for faint stars and meteor showers, come only after astronomical twilight ends, roughly an hour or more after sunset.

How long the dusk lasts depends on where you are. Near the equator the sun drops almost straight down, and it gets dark about 21 to 24 minutes after sunset. In New York it takes about half an hour; in London, 40 minutes in winter and nearly 50 in June; in Edinburgh in June, about an hour, and farther north the sky never gets fully dark on summer nights.

Why isn't the earliest sunset on the shortest day?

The shortest day of the year in the Northern Hemisphere is the December solstice (December 21 this year), but the earliest sunset comes weeks before it and the latest sunrise weeks after. In New York this winter, the earliest sunset is on December 7 (4:28 PM) and the latest sunrise on January 4 (7:20 AM). The reason is that solar noon, the moment the sun is highest, isn't fixed on the clock: around the December solstice it drifts later by about half a minute a day, because Earth moves fastest in its slightly oval orbit in early January and its axis is tilted. The day keeps shrinking at both ends, but the whole day slides later, so evenings start brightening before mornings do.

Why are days longer in summer, and opposite in Australia?

Earth's axis is tilted about 23.4°. For half the year the Northern Hemisphere leans toward the sun, which then climbs higher and stays up longer; for the other half the Southern Hemisphere does.^[35] That's also why the seasons are reversed: when New York has its shortest days in December, Sydney has its longest. This year Sydney gets 14 hours 25 minutes of daylight at the December solstice and only 9 hours 54 minutes in June. Within the Arctic and Antarctic circles the effect becomes extreme: the sun stays up for weeks in summer and doesn't rise at all in midwinter. The tool above says so on those days.

Sunrise, sunset and prayer times

The sunrise and sunset on this page are astronomical: the moments the top of the sun touches a flat horizon. Religious timetables use their own rules. Islamic prayer times such as Fajr and Isha are based on the sun's angle below the horizon, and different organizations use different angles, so the same city can have noticeably different Fajr times in different timetables. For prayer, fasting and other religious times, follow your local mosque, temple or community.

How these times are calculated

We calculate every time from the sun's position for the coordinates of the place you choose, using the standard definitions: sunrise and sunset when the sun's upper edge is on the horizon, with the bending of light by the atmosphere included.^[46] Moonrise and moonset are worked out the same way on our Moon Phase Today page. The city list comes from GeoNames^[37] and uses each city's center. The times assume a flat horizon at sea level: behind mountains or tall buildings the sun appears a few minutes later and disappears earlier, while from a high viewpoint or over the sea you may see it a minute or two longer. Unusual air temperatures near the ground can shift the moment by a minute as well.