Dictionary term
Blue Hour
Direct answer
Blue Hour is an informal photographic period of cool, diffuse twilight light before sunrise or after sunset.
Blue Hour is the cool-toned twilight interval favored by photographers.
Blue Hour is the cool-toned twilight interval favored by photographers.
A Sun–Earth orientation for seasonal, atmospheric, tidal, and terrestrial terms.Quick reference
- Use when
- Use Blue Hour as a planning label alongside actual Sun-altitude times rather than as a fixed sixty-minute period.
- Do not use it for
- Definitions vary by app, often using different negative solar-altitude ranges; state the method when precision matters.
- Reference category
- Seasons & Earth Almanac
- Related terms
- Nautical Twilight, Golden Hour, Astronomical Season, Equinox
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The story behind Blue Hour
Photography and cinematography popularized the term for a twilight quality artists had long observed.
Blue Hour in spiritual tradition
Spiritually, Blue Hour can encourage attentive seeing without turning a color effect into a universal omen.
Blue Hour: fact and faith, kept distinct
This is a factual calendar, astronomy, Earth-science, cultural-history, or observational reference. It can support wonder and practical planning without becoming a claim of fate, spiritual causation, or private revelation.
Blue Hour in numerology
Blue Hour is not a numerology claim. Any numbers attached to it should retain their ordinary scientific, calendrical, navigational, or historical meaning unless a separate symbolic interpretation is clearly labeled.
Why Blue Hour matters
Its balanced sky and artificial-light levels can produce saturated blue scenes, but duration changes with latitude and season.
Blue Hour at work: an example
A high-latitude summer Blue Hour can last far longer than the brief tropical transition.
Where interpretation stops
Blue Hour is presented as sourced astronomy, calendrical, Earth-science, cultural, or instrument-history reference. Definitions should distinguish measured phenomena from civil convention and historical interpretation, preserve location and time dependencies, and avoid turning factual sky data into a deterministic personal claim.
Sources and editorial method
Research references used for this entry include:
- NOAA Global Monitoring Laboratory: Solar Calculator Glossary - NOAA definitions for solar geometry, atmospheric refraction, and civil, nautical, and astronomical twilight.
- National Weather Service: Atmospheric Optics - NWS science reference for halos, pillars, sundogs, green flashes, rays, and related optical displays.
- Source
- The Great Almanac Dictionary
- Category
- Seasons & Earth Almanac
- Also appears in
- Seasons & Earth Almanac
- Aliases
- None listed
- Last updated
- 2026-07-16
Plan the cool-light interval
Blue Hour in a book is one thing; Blue Hour in your own birth chart is your life. The Oracle casts your real chart and tells you what it means for your love, your work, and your year ahead, in conversation, free.
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More in Seasons & Earth Almanac
Common questions
What is Blue Hour?
Blue Hour is an informal photographic period of cool, diffuse twilight light before sunrise or after sunset.
How is Blue Hour used in an almanac?
Use Blue Hour as a planning label alongside actual Sun-altitude times rather than as a fixed sixty-minute period.
What should I avoid when interpreting Blue Hour?
Definitions vary by app, often using different negative solar-altitude ranges; state the method when precision matters.
