What time does it get dark? The answer depends on whether you mean fading outdoor light or the end of astronomical twilight. Compare sunset, civil dusk, nautical dusk and astronomical dusk for the location and date above.
Solar results
Choose a useful definition of dark
Sunset is when the Sun’s upper edge reaches the standard horizon. The sky remains illuminated afterward because the atmosphere still scatters sunlight toward the ground.
Civil dusk occurs when the Sun’s center is 6° below the horizon. It marks the end of the brightest standard twilight stage. It is a useful planning reference for ordinary outdoor light, although your surroundings may become difficult to see earlier.
Nautical dusk occurs at 12° below the horizon. The sky is darker than at civil dusk, but some solar twilight remains.
Astronomical dusk occurs at 18° below the horizon. This marks the end of astronomical twilight. It is the relevant solar boundary when you want to plan around the darkest part of the night, but it does not remove moonlight or light pollution.
How long does it take to get dark after sunset?
Subtract sunset from the dusk boundary you need for the selected date. For example, a sunset at 7:40 PM and civil dusk at 8:10 PM would mean 30 minutes of evening civil twilight. Those are example times, not a rule to apply elsewhere.
The Sun’s angle below the horizon changes at different rates across latitudes and seasons. Near the equator, twilight is often shorter than at high latitudes. A shallow summer path can keep the northern or southern horizon bright for hours. Check your location instead of relying on a fixed 20-, 30- or 60-minute estimate.
Darkness for photography and stargazing
Blue hour occurs before the end of civil twilight under this site’s −6° to −4° convention. It suits scenes where you want some sky brightness alongside artificial lights. Astronomical darkness serves a different purpose: it minimizes the Sun’s contribution to the sky for observing faint objects.
A full or bright Moon can still make an astronomically dark interval unsuitable for faint-sky photography. Urban lighting, haze and cloud matter too. This tool calculates solar events; it does not calculate moonrise, moonset or a sky-brightness score.
When darkness never fully arrives
In some high-latitude summers, sunset occurs but astronomical dusk does not. The Sun remains too close to the horizon throughout the night. Farther poleward, there may be no sunset at all. A missing astronomical dusk should be read as a missing solar threshold crossing, not a prediction of perpetual sunshine.
Use the detailed twilight entries to see which boundaries the Sun does cross. Civil or nautical dusk may still occur even when astronomical night is absent.
Frequently asked questions
What time does it get pitch black?
There is no standardized pitch-black time. Astronomical dusk is the solar benchmark, while moonlight, artificial lighting and the local atmosphere determine how dark the scene looks. Even a remote moonless sky has natural background light.
Does an overcast sky make it dark earlier?
Cloud can reduce remaining natural light and make outdoor surroundings look dark sooner. In cities, cloud can also reflect artificial light and brighten the night sky. Neither effect changes the calculated twilight boundaries.
Is civil dusk safe as a lighting deadline?
Civil dusk describes a solar angle, not the visibility of your route or task. Forest cover, terrain, rain and your own ability to see matter. Use local conditions and an appropriate lighting plan instead of treating the time as a guaranteed threshold.
What is the difference between dusk and twilight?
Twilight is the interval of changing light before sunrise or after sunset. A named dusk marks an evening boundary of that interval. For example, astronomical dusk ends astronomical twilight.