Nautical twilight, evening: Reverse of the morning progression. Good visibility for exercising outside, but you wouldn’t want to be wearing dark glasses, and toward the end of the half-hour you’d want lights or reflectors if you’re near vehicle traffic. Sky starts out pale and dusky, often pinkish. In much of the Bay Area, the sun disappears behind the western hills 10 minutes or more before official sunset - the time at which civil twilight begins.Ĭivil twilight, evening: Reverse of the morning progression. In much of the Bay Area, though, the sun is not visible until about 10 minutes after official sunrise time, because of the hills to the east. Technically, the end of civil twilight coincides with sunrise. Pedestrians no longer need a light to see where they’re going but would probably want reflectors or bright clothing if they’re near traffic, especially on an overcast day. By the midpoint, you can read a newspaper outside under open sky. At the start of civil twilight, the sky is light blue and colors of objects are easier to detect. Bicyclists on the street definitely would want the full complement of lights.Ĭivil twilight, morning: Half an hour in which the sky lightens all over. Trees and buildings can be seen sharply against the sky, but it’s still very dim on the ground - it would be easy to step into a hole, and pedestrians would probably want a flashlight or headlamp. Nautical twilight, morning: Half an hour in which it goes from dark to some lightening of the sky and pale or reddish at the eastern edge. In civil twilight, the sky is light all over though the sun is not visible. Nautical twilight is a deep dusk - dim bluish sky, bright planets visible. The darkest of the twilights is astronomical to an astronomer, it’s not the same as night, but to the layperson it’s close enough. November 2022: On the first day of standard time, the approximate twilight times in the San Francisco Bay Area are: morning nautical twilight 5:40 to 6:10 a.m., morning civil twilight 6:10 to 6:40 a.m., evening civil twilight 5 to 5:30 p.m., evening nautical twilight 5:30 to 6 p.m. Some such sites also include twilight times. To find the current sunrise and sunset times for your area, check an astronomical table, such as that at. Morning twilight ends at sunrise, evening twilight begins at sunset. run require a headlamp? It helps to know the different stages of twilight.Įach about half an hour long, the stages are delineated by the angle of the sun in relation to the horizon. Is there time for an after-work trail ride before dark? Will a 6:30 a.m. Twice a year, when the clocks are changed, runners and cyclists recalibrate their exercise schedules.

Dawn dusk and twilight