Sunrise Sunset Calculator

How the Sunrise Sunset Calculator works

Sunrise and sunset change every day, and by very different amounts depending on where you are. Near the equator days stay close to 12 hours all year. In London they swing between under 8 hours in December and over 16 in June, and inside the Arctic and Antarctic circles the sun can stay up or down for weeks.

How the sunrise sunset calculator works

The calculator uses the solar position equations published by the US National Oceanic and Atmospheric Administration, which are accurate to about a minute for dates within a few centuries of today. For each date it works out the sun's declination, how far north or south of the equator it is overhead, and the equation of time, the few minutes by which the sun runs ahead of or behind the clock through the year. From those and your latitude and longitude it finds the moment the sun crosses each elevation.

Sunrise and sunset are defined as the moment the top edge of the sun touches a flat horizon. Because the atmosphere bends light and the sun is half a degree wide, that happens when the sun's centre is about 0.833 degrees below the horizon. That is the standard used by almanacs and weather services, so the times match published tables.

Reading the results

• Sunrise and Sunset are local clock times in the chosen time zone.
• Solar noon is when the sun is highest, with its elevation above the horizon. It is rarely 12:00, because of time zone boundaries, daylight saving and the equation of time.
• Day length is the time from sunrise to sunset.
• Civil, nautical and astronomical twilight give the morning and evening periods when the sun is just below the horizon.

For London on 1 October 2026, the sun rises at 06:59 and sets at 18:39, giving 11h 40m of daylight, with solar noon at 12:49 and the sun 35.4 degrees high. On 21 June the sun rises at 04:42 and sets at 21:21, a day of 16h 39m. On 21 December it rises at 08:03 and sets at 15:53, giving just 7h 50m, and reaches only 15.1 degrees at noon.

The three kinds of twilight

Twilight is the time when the sun is below the horizon but still lighting the sky. It is split by how far below the horizon the sun is:

Civil twilight is what most people call dusk and dawn, and many vehicle lighting and aviation rules refer to it. Nautical twilight was traditionally when sailors could take star sightings against a visible horizon. Astronomers wait for the end of astronomical twilight for true darkness.

In summer at higher latitudes some twilight stages never end. In London on 21 June, nautical twilight runs from 22:09 until 23:23, and the sun never gets 18 degrees below the horizon, so astronomical twilight and true darkness do not occur that night.

Midnight sun and polar night

North of the Arctic Circle and south of the Antarctic Circle, the sun can stay above the horizon all day in summer or below it all day in winter. The calculator reports these as Midnight sun or Polar night instead of a sunrise or sunset. In Tromsø, Norway, on 21 December the sun stays 3.1 degrees below the horizon at noon, but civil twilight still lights the sky from 09:30 to 13:53.

Getting accurate coordinates

Enter latitude and longitude in decimal degrees, with north and east positive and south and west negative. Four decimal places pin a spot to about 11 metres, far more than sunrise needs: moving 1 degree of longitude east or west shifts sunrise by about 4 minutes. If your coordinates are in degrees, minutes and seconds, convert them first.

Pick the time zone that matches the place, not where you are now. The default list covers major cities; your browser offers every IANA zone when it can.

Limits

The times assume a flat, sea-level horizon. Hills, buildings and mountains delay the visible sunrise and bring forward sunset, sometimes by many minutes in a valley. Standing high up, on a mountain or in an aircraft, lets you see the sun earlier and later. Unusual air temperatures change refraction slightly, so real times can differ from any calculation by a minute or two, especially near the poles where the sun skims the horizon.

How many hours of daylight London gets through the year

The formula is the NOAA solar position method: sunrise and sunset are when the sun's centre sits 0.833° below the horizon, which allows for refraction and the sun's radius. For example, London has 16h 37m of daylight on 15 June and just 7h 52m on 15 December. Each example below is in local clock time, so it includes British Summer Time.

Sunrise and sunset in London through 2026, local clock time

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