Civil twilight calculator
When does civil twilight start and end today?
Part 107 uses a fixed 30-minute civil twilight outside Alaska, not the one your weather app shows. Pick a city or ZIP and see today's official sunrise and sunset, the Part 107 twilight windows, and what each phase requires.
Calculating today's sunrise, sunset and civil twilight…
Civil twilight questions
- How long is civil twilight under Part 107?
- Outside Alaska, exactly 30 minutes: the half hour before official sunrise and the half hour after official sunset (14 CFR 107.29(c)). In Alaska it is civil twilight as defined in the Air Almanac, which follows the sun's position and can last much longer.
- Why does my weather app show a different civil twilight time?
- Weather and photography apps define civil twilight by geometry: it ends when the sun's center is 6 degrees below the horizon. That takes more or less than 30 minutes depending on latitude and season. Part 107 uses the fixed 30 minutes outside Alaska.
- What do I need to fly a drone during civil twilight?
- Lighted anti-collision lighting visible for at least 3 statute miles with a flash rate sufficient to avoid a collision. The night training requirement in 107.29(a) applies at night, not during civil twilight.
- What do I need to fly at night under Part 107?
- The same anti-collision lighting, plus an initial knowledge test or training completed after April 6, 2021, as required by 107.29(a). You may dim the light if conditions call for it, but you may not turn it off.
Read more: night operations under Part 107, Alaska's Air Almanac rule, and the text of 14 CFR 107.29.