Golden hour: sun between −4° and +6°. Blue hour: −6° to −4°. Sunrise and sunset at −0.833°, the refraction-corrected horizon. Accurate to about a minute, computed in your browser.
How it knows
The whole day, painted with the sun's own altitude: golden hour bright beneath the band, blue hour receding.
Golden hour · am—
Golden hour · pm—
Blue hour · am—
Blue hour · pm—
Day length—
What golden hour actually is
Not sixty minutes: the span with the sun between −4° and +6°, when its light crosses a long slice of air and arrives warm and low.
Why the times move so much
Near the equator the sun punches through the band; at high latitudes it lingers — tonight's window, at three latitudes.
Blue hour
From −4° to −6° the light is gone but the sky still glows, even and shadowless — shorter, and worth planning for.
Golden hour, every evening, on your wrist — before you ask.
Sol for iPhone · Coming soon