Sunrise and sunset

How it works

Sunrise counts from the moment the upper edge of the sun appears at the horizon, not when its centre crosses. The atmosphere also bends the light, so the sun is visible while it is still geometrically below the horizon. Together these make the day a few minutes longer than pure geometry would give.

That is why the day runs a little over twelve hours at the equinoxes, despite the name suggesting that day and night should be equal.

The sun is highest at solar noon, which rarely falls at twelve o’clock. Two things move it: where in its time zone the place sits, and the equation of time, which comes from the elliptical orbit and the tilted axis. A sundial can be a quarter of an hour out from the clock depending on the season.

Twilight is divided into three stages by how far below the horizon the sun sits. Civil twilight is bright enough to read outdoors, nautical still shows the horizon at sea, and after astronomical twilight the sky is fully dark.

North of the Arctic Circle the sun stops rising and setting for part of the year. Midnight sun or polar night is then shown instead of clock times.

The times use the NOAA algorithms and are accurate to about a minute. Very close to the poles the sun meets the horizon at such a shallow angle that a small difference in altitude makes a large difference in time, and there the times should be read as approximate.

The solstices of 2026 in the United Kingdom

Sunrise, sunset and the length of the day at the June and December solstices for five cities from south to north, in local time with British Summer Time where it applies. The figures use the same method as the tool above.

In London the earliest sunset of the year falls on 13 December at 3:51pm, a few days before the December solstice, and the latest sunrise on 30 December at 8:06am, a few days after it.

From the Lizard to Shetland

The mainland of Great Britain runs from the Lizard peninsula at about 49 degrees 57 minutes north to Dunnet Head at 58 degrees 40 minutes, and Shetland reaches past 60 degrees 50 minutes. The further north you go the longer the summer day and the shorter the winter one, because the sun follows a flatter arc.

At the equinoxes in March and September the day is close to twelve hours everywhere in the country. It is at the solstices that the difference between north and south is largest: at the June solstice Lerwick in Shetland has about two and a quarter hours more daylight than London.

No midnight sun, but the simmer dim

Nowhere in the United Kingdom lies north of the Arctic Circle, so the sun always rises and sets. In Shetland it barely gets dark around midsummer, because the sun stays close to the horizon all night. Islanders call it the simmer dim.

The opposite happens in December. In the far north of Scotland the sun is up for less than six and a half hours at the solstice, and the twilight before and after it is long, because the sun climbs so little above the horizon.

Why the darkest evening comes before the solstice

The December solstice is the shortest day, but it is not the day the sun sets earliest. Solar noon moves about half a minute later each day through December, because the earth’s orbit is elliptical and its axis is tilted. The earliest sunset therefore falls before the solstice and the latest sunrise after it.

That is why the evenings start to draw out noticeably in late December while the mornings stay dark into January.

British Summer Time moves the clock, not the sun

British Summer Time runs from the last Sunday in March to the last Sunday in October, when the clock is one hour ahead of Greenwich Mean Time. The sun then reaches its highest point closer to one o’clock than to noon, and both sunrise and sunset come an hour later by the clock than they otherwise would.

The tool always shows local time for the place, with summer time included when it applies.

Sources

• NOAA Solar Calculator
• U.S. Naval Observatory – Rise, Set, and Twilight Definitions
• HM Nautical Almanac Office
• Summer Time Order 2002

How the tools are checked