Sunset Today

Sunset is the moment when the upper edge of the sun disappears below the horizon in the west. Like sunrise, the time of sunset changes every day — shifting by as much as five or more hours between winter and summer at mid-latitudes. As the sun sets, it doesn't simply go dark: a sequence of twilight phases follows, each with its own quality of light.

Use the tool on the homepage to see the exact sunset time for your location today.

Sunset times through the year — London (51°N)

* Clocks spring forward one hour at end of March. ** Clocks fall back at end of October.

The three phases of twilight

After the sun dips below the horizon, light doesn't vanish immediately. There are three distinct twilight phases, each defined by how far below the horizon the sun sits:

Civil twilight — the sun is between 0° and 6° below the horizon. This is the brightest phase: the horizon is still clearly visible, outdoor activities are possible without artificial light, and the sky glows with warm colour. Civil twilight ends roughly 20–30 minutes after sunset at mid-latitudes.

Nautical twilight — the sun is between 6° and 12° below the horizon. The horizon is no longer clearly visible; this is the phase historically used for navigation by stars while still being able to see the horizon. Brighter stars become visible. Duration: roughly another 30 minutes.

Astronomical twilight — the sun is between 12° and 18° below the horizon. Sky brightness has fallen enough for most astronomical observations; only the faintest objects remain obscured by residual glow. Once the sun drops below 18°, it is considered full night.

At high latitudes in midsummer, the sun may never drop below 18° — or even 12° — so true astronomical night never arrives. This is the phenomenon behind the famous white nights of St Petersburg and the Scandinavian summer.

Golden hour and blue hour

Photographers prize the period around sunset for its quality of light. The golden hour — roughly the last hour before sunset and the first after — produces warm, low-angle light that flatters landscapes and portraits. Immediately after the sun sets, the sky shifts to cooler blues during blue hour (civil twilight): softer, more diffuse, ideal for cityscapes where artificial lights begin to appear. Both windows are brief and vary by latitude and season, so knowing your exact sunset time matters.

The midnight sun — when sunset doesn't come

Above the Arctic Circle in summer, the sun circles the sky without setting. In Tromsø, Norway (70°N), the sun doesn't set for about two months around the summer solstice. Conversely, the same region experiences polar night in winter — the sun rises briefly or not at all. Near the equator, this phenomenon never occurs: sunset happens within minutes of 18:00 local time every day of the year.

Check the exact sunset time for your location on the homepage, and explore the full yearly cycle of sunrise and sunset with the interactive chart.

Why sunsets are red

The colour is not something the sun does — it is something the atmosphere does to it, and it is the same effect that makes the daytime sky blue.

Air molecules scatter short wavelengths far more strongly than long ones, an effect named after Lord Rayleigh who worked out the relationship. Overhead at midday, sunlight passes through relatively little atmosphere, so only some of the blue is scattered out of the beam and redirected across the sky — which is why the sky is blue and the sun still looks white.

At sunset the light arrives at a shallow angle and has to travel through something like forty times as much air to reach you. By the time it does, essentially all the blue and green have been scattered away, leaving the reds and oranges to come through directly. The sun looks red for the same reason the sky is blue: the blue has gone somewhere else.

This is why the most spectacular sunsets tend to follow the passage of a weather front, when the air is clean and there is high cloud left behind to catch the light from below. Contrary to the folk version, haze and pollution generally make sunsets duller rather than better — large particles scatter all wavelengths more evenly and wash the colour out. Volcanic aerosol in the stratosphere is the exception, and can produce extraordinary sunsets worldwide for months.

Where on the horizon the sun actually sets

"The sun sets in the west" is true only twice a year. On every other date it sets somewhere north or south of due west, and at high latitudes the range is enormous.

At the equinoxes the sun sets almost exactly due west everywhere on Earth. Through spring the sunset point swings northwards, reaching its extreme at the June solstice, then swings back and past west to its southern extreme in December. In London the sunset bearing ranges from roughly 310° in June to about 230° in December — an arc of eighty degrees. In Copenhagen it is wider still.

The practical consequences are easy to underestimate. A west-facing window that catches the sun in March may miss it entirely in December. A viewpoint that works for midsummer sunsets can have a hill in the way for the rest of the year. And if you are photographing a sunset behind a specific landmark, the date is not a detail — it is the whole problem. Each city page on this site gives today's sunset bearing for exactly this reason.

Green flashes and other rarities

The green flash is real, not folklore. For a second or two as the last sliver of sun disappears, the top edge can turn a vivid green. The cause is refraction: the atmosphere acts as a weak prism and separates the colours slightly, so the green image of the sun sets a moment after the red one. Normally the difference is too small to notice, but with a sharp, distant horizon — the sea is ideal — and clean stable air, that final green rim becomes briefly visible on its own.

Two other effects worth knowing. The setting sun often appears visibly flattened, wider than it is tall, because refraction lifts the lower limb more than the upper one. And the sun you are watching touch the horizon is, strictly, not there any more: refraction has already lifted its image by roughly its own diameter, so geometrically it has set before you see it set. That same refraction is a large part of why the day is never exactly twelve hours long at the equinox — the detail is on the how we calculate the times page.

Frequently asked questions about sunset

What time is sunset today?

Sunset depends on where you are. In London it falls as late as about 21:23 in late June and as early as about 15:52 in mid-December. Use the calculator on the front page for the exact time at your location today.

Why is the earliest sunset not on the shortest day?

Because of the equation of time. In London the earliest sunset falls around 11 December at about 15:52, ten days before the December solstice. Solar noon keeps drifting later through December, so sunset starts pulling back before the shortest day arrives.

How long does it stay light after sunset?

That depends on latitude. Civil twilight lasts about 48 minutes after a June sunset in London, but barely more than 20 minutes in Singapore, where the sun drops towards the horizon at a much steeper angle.