Outdoor movie night planner
A film under the stars needs a dark sky. Pick a date and place to see when the sun sets, when it gets dark enough to start, and when your film will finish.
Saturday 15 August 2026 · London (51.5074° N, 0.1278° W), times in UTC+01:00, summer time
- Sunset
- 20:23The top of the sun dips below the horizon (sun 0.833° down).
- Civil dusk
- 21:00Sun 6° below the horizon: outdoor lights are needed.
- Nautical dusk
- 21:48Sun 12° below the horizon: the sky is nearly dark.
Admit one · Recommended start
21:00
Civil dusk: the sun is 6° below the horizon and the sky is dimming fast. A bright projector on a modest screen is watchable from here, and the picture keeps improving as the sky darkens towards nautical dusk at 21:48.
Outdoor screening checklist
How it works
The planner works out where the sun is with the same equations as the NOAA Solar Calculator, all inside your browser. Sunset is when the top of the sun drops below a flat horizon (its centre 0.833° down, allowing for the air bending the light). Civil dusk is when the centre of the sun is 6° below the horizon and you need lights to do things outdoors; nautical dusk, at 12°, leaves the sky close to dark.
The recommended start is your chosen dusk, rounded up to five minutes: a bright projector on a small screen copes at civil dusk, a dimmer one or a big picture looks better from nautical dusk. If the sun never gets that far down, the planner says so and suggests the darkest time of night. The end time adds your extras and the runtime.
Times use the place's own time zone; built-in cities know their summer-time rules. Hills, trees and cloud make it darker sooner than a flat horizon would.
Sources
- Solar position, sunrise and sunset equations (after Jean Meeus, Astronomical Algorithms), the 0.833° allowance for refraction, and accuracy "within a minute" between 72° north and south: NOAA Global Monitoring Laboratory, Solar Calculation Details. Checked against NOAA's own sunrise and sunset tables for London, New York, Sydney, Reykjavík and Tromsø.
- Sunset at 90.8333° zenith, and civil and nautical twilight ending with the sun's centre 6° and 12° below the horizon: US Naval Observatory, Rise, Set, and Twilight Definitions.
- Summer-time rules for the built-in cities: EU and UK, Directive 2000/84/EC (last Sunday of March to last Sunday of October); United States, 15 U.S. Code § 260a (second Sunday of March to first Sunday of November); Daylight saving in NSW (first Sunday of October to first Sunday of April, also kept by Victoria, South Australia, Tasmania and the ACT); Daylight saving in NZ (last Sunday of September to first Sunday of April).
Questions
How long after sunset can we start the film?
It depends on where you are and the time of year: near the equator civil dusk comes about 20 to 25 minutes after sunset, while in a northern summer it can take an hour or more. Enter your date and place to get the real figure rather than a rule of thumb.
Why does it say it never gets dark?
In summer, places far from the equator have "white nights": the sun dips below the horizon but never gets 6° or 12° below it, so the sky stays light all night. North of the Arctic Circle around midsummer the sun doesn't set at all. Plan for a very bright projector, a smaller picture, or a date later in the year.
Does "Use my location" send my position anywhere?
No. Your browser asks your permission, then gives the coordinates to this page, which fills them in and does the sums on your device. Nothing is sent to Reel Picnic or anyone else, and the planner doesn't save it: reload the page and it's gone.