Golden hour in Santa Cruz de la Sierra, Bolivia today

Golden hour is defined here by the sun’s altitude, not by a fixed number of minutes. It runs while the sun sits between +6° and −4° relative to the horizon: high enough to still light the scene, low enough that the light has travelled through a long path of atmosphere and lost its blue.

Below −4° the direct light is gone and blue hour takes over, running to −6° where civil twilight ends. Because the definition is angular, the length of golden hour depends on how steeply the sun meets the horizon — which is a function of latitude and season, not of the clock. That is why it lasts 42m here today and about 41 minutes at the equator.

Full definitions of every term used here — golden hour, blue hour, altitude, azimuth — are in the glossary.