Find blue hour today for morning and evening photography. The tool uses the interval when the Sun’s center is between 6° and 4° below the horizon. This is a defined planning window within twilight, not a guaranteed sky color.
Solar results
When blue hour occurs
Morning blue hour begins at −6° and ends as the Sun rises through −4°, before sunrise. Evening blue hour begins at −4° and ends at −6°, after sunset. Under this site’s conventions, it sits directly beside the golden-hour window.
The Sun is below the horizon during this interval, so the scene is lit by the sky rather than direct sunshine. The balance between that ambient light and lamps, windows or signs can make buildings easier to photograph than in complete darkness.
Use blue hour for a balanced scene
Choose the composition before the window begins and watch the balance between bright artificial lights and the fading sky. A scene can change noticeably within a few minutes. Take more than one exposure as the light changes instead of expecting a single listed time to be the best moment.
A tripod may help when exposure times become longer, but moving people, foliage or water will behave differently from a stationary building. Your camera’s exposure and white-balance choices also affect whether the sky appears blue, pale or nearly black.
Blue hour, twilight and darkness
Blue hour is a photography convention. Civil twilight is an astronomical stage whose darker boundary is at −6°. The blue-hour interval used here is a portion of civil twilight, not the entire period between sunset and night.
Astronomical dusk occurs later, at −18°, where that boundary is reached. If your aim is a dark sky for faint stars, use the darkness page and consider moonlight and local lighting as well.
Why the window may be short or missing
Duration changes with the angle of the Sun’s path. At some locations the defined band passes quickly; at others it lasts much longer. High-latitude summer dates can lack one or both crossings if the Sun never descends far enough or remains within a narrow altitude range.
Cloud cover can also make the scene gray or obscure the horizon without changing the calculated window. A result is a timing guide, not a forecast of the photograph’s color.
Frequently asked questions
How long after sunset does blue hour start?
There is no fixed delay. On this site it starts when the Sun reaches −4° in the evening. Compare the sunset time and the blue-hour start for your selected date and coordinates.
Can blue hour happen before sunrise?
Yes. The morning interval occurs as the Sun rises from −6° to −4°. It comes before both sunrise and the later part of morning golden hour.
Why do blue-hour calculators disagree?
The phrase does not have a universally fixed scientific definition. Different tools choose different solar-altitude bands or photographic rules. Compare the stated boundaries along with location and time zone.
Does blue hour end when the sky stops looking blue?
Not necessarily. The tool ends its window at a chosen solar altitude. Weather, viewing direction, light pollution and camera settings can make blue tones appear earlier or remain later.