What Time Does Night Start? Nightfall vs Evening
Learn how nightfall, sunset, twilight, and everyday clock-time conventions differ when someone says it is night.
What Time Does Night Start? Nightfall vs Evening
Night does not begin at the same clock time everywhere. In ordinary conversation, night often means the darker hours after evening begins. In astronomy, darkness is described using sunset and successive stages of twilight. The exact start depends on whether you mean a social daypart, the moment after sunset, or the onset of astronomical darkness.
The short answer: what counts as night?
If you are arranging a phone call or dinner, someone may call 7 p.m. or 8 p.m. “night.” That is an informal convention, not a fixed worldwide rule. If you are asking when the sky becomes dark enough to observe stars, you need a local twilight time for a specific date.
This difference explains why “It is night at 6” can sound right in midwinter but strange on a bright summer evening. It also explains why a nighttime event can start while traces of twilight remain in the sky.
Nightfall, sunset, and the twilight stages
Sunset is the moment the Sun disappears below the horizon. It is not necessarily the moment of full darkness. After sunset, light scattered through the atmosphere can keep the sky bright for a while. This interval is called twilight.
Civil twilight ends when the Sun's geometric center reaches 6 degrees below the horizon. Nautical twilight extends to 12 degrees below, and astronomical twilight to 18 degrees below. After astronomical twilight ends, the sky may be considered astronomically dark, although moonlight, city lighting, weather, and high-latitude conditions still affect what you see.
| Moment | What it tells you | Is the sky completely dark? |
| Sunset | The Sun has just disappeared | Usually not |
| End of civil twilight | Strongest after-sunset twilight has faded | Not necessarily |
| End of nautical twilight | Deeper twilight has passed | Not necessarily |
| End of astronomical twilight | Astronomical twilight is over | Darker skies are possible, not guaranteed |
The same sequence occurs before sunrise in reverse. For people planning outdoor activities, the end of civil twilight may be a more useful measure than a vague promise that the event “starts at night.”
Is evening the same as night?
No. Evening is an everyday label for a later part of the day. Night refers more directly to darkness or late hours, depending on context. The two can overlap; they are not mutually exclusive categories with a sharp clock-time boundary.
For example, “an evening concert” describes the event's schedule. “A clear night sky” describes the viewing conditions. A concert can be held during twilight, while a dark sky may arrive before a person has finished the early-evening commute.
How to find the start of night in your city
Look up the location and date in an astronomical calculator from a recognized time or weather authority. Choose whether your activity needs sunset, civil dusk, nautical dusk, or astronomical dusk. Double-check the local time zone, since the clock reading for sunset can jump after a daylight saving time change even when the actual solar cycle changes gradually.
For hiking or photography, do not rely on a blanket statement such as “night falls at 7 p.m.” A calculated time is helpful, but weather and terrain can reduce usable light earlier. Carry a suitable light if the activity may extend into dusk.
Why the length of night changes
The amount of time between sunset and sunrise changes with latitude and season because of Earth's axial tilt. At some high latitudes, the Sun may remain above the horizon for a long period in summer or below it for an extended period in winter. The definitions of civil and astronomical twilight also behave differently in these situations.
That means a reliable explanation must give the location and date, not just the month or a generic US average. It also means that an overnight work shift is not the same as a measured astronomical night: the employer sets the shift hours.
If your question is about writing the word itself, see nighttime versus night time.
Frequently asked questions
Is 7 p.m. considered nighttime?
It often is in conversation. Whether the sky is actually dark at 7 p.m. varies with location, season, and twilight conditions.
Does night start when the Sun sets?
Sunset starts the after-sunset twilight period. Complete astronomical darkness, where it occurs, begins later.
What is the difference between dusk and nightfall?
Dusk has technical twilight uses, while nightfall broadly describes the arrival of darkness. The latter is less precise.
Why is it still light after sunset?
Sunlight continues to scatter through the atmosphere while the Sun is below the horizon. That remaining illumination is twilight.