Golden hour is the spell around sunrise and sunset when the sun sits low — in Sol's measure, between 6° above the horizon and 4° below it.

Sol measures it by the sun's altitude, not the clock: from 6° above the horizon down to 4° below in the evening, and the reverse in the morning. That is why it lasts about forty minutes near the equator, where the sun drops steeply, and well over an hour in the north, where it slides along the horizon. In midsummer above the Arctic Circle the sun never leaves the band, and the golden hour is the whole night.

It is warm because the light crosses far more air on its way to you, which scatters the blue away, and soft because it comes in sideways.