A field guide to better light
What time is blue hour?
A cool, dim sky for cityscapes, silhouettes and the transition into night. Choose one of our five reviewed cities for today’s local times.
Chicago · · America/Chicago
Morning blue hour
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11 minutes
Evening blue hour
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11 minutes
What is blue hour?
Blue hour is a twilight interval when indirect sunlight can give the sky a cool blue appearance. Here it means the Sun’s geometric center is between −6° and −4° altitude: rising in the morning and falling in the evening. The term has no single universal boundary; this explicit convention makes our calculations comparable across cities.
How long does blue hour last?
“Hour” is a name, not a fixed sixty-minute duration. The Sun crosses the selected altitude band at different speeds depending on latitude and season. The cards above subtract the actual event instants to show today’s duration in Chicago. Around high-latitude summer or winter, some altitude crossings may not happen at all. Clouds, haze and nearby buildings can shorten the light you can use.
Blue hour and golden hour
Blue hour usually requires longer exposures than golden hour because the Sun is below the horizon. Compare golden hour in Chicago →
Blue hour by city
Blue hour photography tips
- Use a tripod or stable support for longer exposures.
- Balance the sky with street lighting before the sky becomes fully dark.
- Check the histogram: bright signs and windows may clip even in a dim scene.
- Allow time to pack up and leave safely after evening twilight.