Twilight
Civil, nautical, and astronomical twilight
Twilight is a set of phases defined by how far the sun is below the horizon. Each one looks and feels different outdoors, and their length changes a great deal with latitude.
By SunCast team Last updated: October 14, 2026
Short answer
Civil, nautical, and astronomical twilight are phases of daylight before sunrise or after sunset. Civil twilight happens when the sun is 0 to 6 degrees below the horizon, nautical twilight from 6 to 12 degrees, and astronomical twilight from 12 to 18 degrees.
Twilight phases by sun angle
| Term | Meaning |
|---|---|
| Civil twilight | Sun is 0 to 6 degrees below the horizon. |
| Nautical twilight | Sun is 6 to 12 degrees below the horizon. |
| Astronomical twilight | Sun is 12 to 18 degrees below the horizon. |
| Night | Sun is more than 18 degrees below the horizon. |
Civil twilight
Civil twilight is the brightest phase. There is usually enough light for most outdoor activities, although you may need a torch in a forest or under heavy cloud.
For photographers, civil twilight keeps detail in the sky while city lights and lit windows start to show.
Nautical twilight
Nautical twilight is darker. The horizon is still visible in open areas, and the scene has a stronger evening or pre-dawn feel.
It suits seascapes and skyline photos, and it tells you how quickly light is fading on a route.
Astronomical twilight
Astronomical twilight is the last phase before full night. The remaining sunlight is faint and the sky is close to fully dark.
It matters for stargazing and night photography, because faint stars and the Milky Way only show well once it ends.
How long each phase lasts at different latitudes
Near the equator the sun drops almost vertically, so twilight is short and steady. In Quito each phase lasts about 21 to 26 minutes, and full night arrives 70 to 75 minutes after sunset in March, June and December alike.
In Madrid on 21 June, civil twilight lasts 33 minutes after the 21:49 sunset, nautical 42 minutes and astronomical 50 minutes, so night only begins at 23:54 CEST. On 21 December the three phases take 31, 34 and 33 minutes.
Further north the phases stretch and then stop ending. In Aberdeen on 21 June civil twilight lasts 69 minutes after the 22:09 sunset, and the sun then sinks no lower than 9.4° below the horizon, so nautical twilight continues until dawn and there is no astronomical night at all. In Tromsø on 21 June the sun stays at least 3.1° above the horizon all night. On 21 December it never rises there; it peaks at 3.1° below the horizon at 11:43, and civil twilight from 09:32 to 13:54 is the brightest the day gets (all figures calculated with SunCast’s sun calculator).
Practical uses
Walking or hiking
Civil twilight is usually the most useful planning phase because there is still meaningful ambient light. At higher latitudes it can add more than an hour.
Coastal or skyline photography
Nautical twilight balances a darker sky with a visible horizon and artificial lights.
Night sky planning
The end of astronomical twilight tells you when the sky is dark enough for faint stars. North of about 48.5°, which takes in London and Paris, it does not end at all around midsummer.
Limits
Twilight angles describe the sun’s position. Clouds, haze, city light and terrain change how bright the sky actually looks.
Check it in SunCast
Need local twilight times? SunCast’s Sun Times & Position Data shows civil, nautical and astronomical twilight alongside sunrise, sunset, golden hour and blue hour.
Frequently asked questions
Which twilight phase is brightest?
Civil twilight, because the sun is closest to the horizon.
When does night begin?
Night begins after astronomical twilight, when the sun is more than 18 degrees below the horizon. Around midsummer north of about 48.5°, including all of the UK, the sun never gets that low and astronomical night does not begin.
Is blue hour the same as twilight?
Blue hour happens during part of twilight, but it is a photography term rather than one of the formal twilight angle ranges. SunCast’s web tools treat it as the sun between 4 and 8 degrees below the horizon.
