It is well known that we are in the time of maximum sunshine, but what may be less widely discussed is that we are also in a period of long and late twilight.

Light does not vanish from the sky the moment the sun goes down. Instead, it lingers in the sky, fading slowly, and never more slowly than in the days before and after the summer solstice.

In theory, at least, the last lingering vestiges of the sun’s illumination do not give way to total nighttime blackness until the end of what is called astronomical twilight.

On Friday, according to the Time and Date website, that did not occur here until 10:33 p.m.

And Saturday morning, only a little more than five hours later, the first faint photons of solar light will again be perceptible, heralding the arrival of dawn and the glories of the sunrise.

It is not guaranteed that anyone’s eyesight will be so sensitive as to actually note the precise start of Saturday’s or any morning’s astronomical twilight.

But according to the laws of physics and geometry, 3:43 a.m. Saturday will mark the end of the hours of total night and darkness.

Meanwhile, Washington’s temperatures on Friday never reached 80, offering splendid and hardly summerlike conditions for enjoying daylight or twilight.