Blue Hour – When It Is & How to Use It for Photos
Learn what the blue hour is, the Chappuis absorption science behind it, and get expert photography tips. Live countdowns for the next blue hour worldwide.
What is Blue Hour?
Blue hour is the twilight period when the sun is between 4° and 6° below the horizon. It occurs twice daily — just before sunrise and just after sunset — when indirect sunlight is scattered by Earth's upper atmosphere, creating a predominantly blue spectrum that bathes the world in ethereal, cool-toned light.
Unlike the warm embrace of golden hour, blue hour offers a completely different emotional palette: mysterious, serene, and otherworldly. It's the moment when natural light and artificial city lights reach a perfect balance, making it the premier time for cityscape and architectural photography.
Chappuis Absorption
During blue hour, the ozone layer absorbs red and orange wavelengths through a process called Chappuis absorption. This leaves blue light dominant, creating the characteristic deep blue sky.
Light Balance
The ambient blue skylight and warm artificial lights are nearly equal in intensity. This creates a unique dynamic range that no other time of day offers — windows glow warm while the sky remains a rich blue.
Alpine lake during blue hour — the deep blue sky and snow reflections create a serene atmosphere
Use a Tripod
Blue hour light is dim. You'll need exposures of 1–30 seconds, making a sturdy tripod essential for sharp images.
Shoot in RAW
The subtle tonal gradations during blue hour are easily lost in JPEG compression. RAW files preserve the full dynamic range for post-processing.
Include Artificial Light
The magic of blue hour photography lies in the interplay between cool sky and warm city lights. Include streetlights, windows, or neon signs.
Bracket Your Exposures
The contrast between bright lights and dark sky can exceed your camera's dynamic range. HDR bracketing helps capture both extremes.
White Balance: Daylight
Set your white balance to daylight (5,500K) to preserve the natural blue tones. Auto white balance may try to 'correct' the blue away.
Evening > Morning
Evening blue hour is often preferred — city lights are already on, and you can compose during the brighter preceding golden hour.
How Long Does It Last?
Blue hour is even more fleeting than golden hour — typically lasting only 20 to 40 minutes. Near the equator, it can be as brief as 15 minutes, while at higher latitudes during the right season, it can extend significantly. In extreme polar locations, blue hour can last for hours during the weeks surrounding the winter solstice.
Timing is everything. Use the live tracker below to know exactly when blue hour begins in cities around the world.
Where the light comes from
Tap a day to open it above. Moon icon: a bright moon stands in the sky during the evening window.
Today in other cities
The farther from the equator, the flatter the sun's path – and the longer the light lasts.
How is the golden hour defined? SunnyTracker counts the time in which the sun is between 4° below and 6° above the horizon – the golden hour begins where the blue hour ends. The light is warm and soft because it passes through a lot of atmosphere.
Does the weather matter? The times are astronomical and assume a clear horizon. Thin clouds often make the golden hour even more colourful; a thick bank of cloud at the horizon can end it early.
How is the blue hour defined? SunnyTracker counts the time in which the sun is between 4° and 6° below the horizon – the part of twilight in which the sky is a deep, even blue.
Do I need a tripod? Usually yes: exposures of one to several seconds are common. Start around ISO 100–400 and f/8 and lengthen the exposure as the light fades.