Updated November 2026 · Photo guide
For beginners shooting city lights or water at dusk. Tap a mistake to flip it to the fix.
Blue hour is the deep-blue stretch of twilight when the sun is about 4° to 8° below the horizon, after sunset or before sunrise. At mid-latitudes it lasts roughly 20 to 30 minutes and starts about 20 minutes after sunset. People miss it mostly by leaving at sunset, or by arriving at sunrise for the morning one.
The term isn't official. The angles come from timeanddate's blue hour guide, which says the blue is most likely between 4° and 8° below the horizon and that it lasts about 20 minutes around 40° north in March, about 16 minutes in Quito and about 30 near Oslo. Those angles sit inside the civil and nautical twilight bands that the U.S. Naval Observatory defines at 6° and 12°.
Blue hour starts when most people have already left, and ends before they'd think to come back.
A sunset photo is the end of the show for most people. For blue hour it's the interval. The light you want arrives after the warm colour fades, while the sky still holds enough brightness to show detail.
Morning blue hour is the mirror image of the evening one, so it happens before the sun is up. If you arrive at sunrise you get golden hour, which is lovely, but not what you came for.
Cameras and phones try to make scenes look neutral. At blue hour that means warming the sky toward grey. timeanddate's guide suggests shooting RAW or TIFF so you can bring the cool tones back when editing.
Low light means slow shutter speeds or high ISO. timeanddate's tips include a tripod with a slow shutter, a higher ISO if you can't use one, and HDR mode on phones to balance sky and subject.
The name oversells it. timeanddate puts it at about 20 minutes around 40° north in March. In the tropics it can be closer to 15; in Oslo, about half an hour.
This one is our view rather than a rule: for skylines, the moment to aim for is when the sky and the artificial lights are about equally bright. That usually lands somewhere in the middle of the window, not at the end.
An illustration, not a real shoot.
Sunset at 4:38. The crowd on the footbridge takes its photos of the orange sky and drifts off by 4:45. You stay, set the tripod and switch white balance to daylight. At 4:57 the sky goes from grey to a clean, deep blue, and the office windows across the river match it for brightness. By 5:15 the sky is too dark and the lights are blowing out. You've got about fifteen frames from a twenty-minute window, and two of them are keepers.
One design decision shaped Asterfold: blue hour gets its own colour band, not a footnote. The Light Path Studio draws the sun's real path for any place and date, coloured by golden hour, blue hour and twilight, and calculated on your iPhone so it works offline. When you plan a session you can choose the light window (golden hour, sunset or blue hour), add composition notes, gear, a reminder and a short checklist.
Worked out on this page for a flat horizon, using the 4° to 8° window. "Starts" is minutes after sunset; "lasts" is the length of the blue. Notice it starts later, and lasts longer, the farther you are from the equator.
| City | Mar 20 | Jun 21 | Dec 21 |
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Each cell: starts +minutes after sunset, then how long it lasts. Morning blue hour is the mirror image, before sunrise.
In the evening, blue hour comes after golden hour and sunset. In the morning it's the other way round: blue hour first, then sunrise and golden hour.
Usually 20 to 30 minutes at mid-latitudes. timeanddate gives about 16 minutes in Quito near the equator and roughly 30 minutes near Oslo at the equinoxes.
Pick a fixed setting such as daylight instead of auto, so the camera doesn't warm the blue away, and shoot RAW if you can so you can adjust it later.
Yes. Brace the phone or use a small tripod, try HDR or night mode, and expose for the sky. timeanddate suggests your phone's HDR mode to balance sky and subject.
Yes. Free includes the Light Path Studio, aiming and plans for 2 viewpoints, the field journal, tonight's ratings and the next 3 evenings. Asterfold Plus is optional and adds unlimited viewpoints, sky alerts and the full 10-day outlook.
If you shoot the Milky Way, blue hour is your warm-up, not your subject; you want astronomical darkness, which comes later. If you only want the sunset itself, any weather app's sunset time will do.
All times here assume a flat horizon, and so does Asterfold: its listing says hills, buildings and trees are not modelled. Neither can promise a clean blue; heavy cloud turns it grey. Asterfold's ratings are labelled as a rule-of-thumb estimate, not a probability.
Blue hour bands, session plans and the field journal are free in Asterfold.