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The timing of sunset
varies with the time of year and the latitude of the location
from which it is viewed (and, in local time, with the location's
precise longitude). Changes in timing of sunset are driven by
the axial tilt of Earth and the planet's movement around its orbit,
however in the Northern Hemisphere (for example), the earliest
sunset is not at the winter solstice around December 21, but rather
in early December. Likewise, the latest sunset is not around June
21 (the summer solstice), but in early July. (The dates may be
swapped for sunset timings in the Southern Hemisphere.) For one
or two weeks surrounding both solstices, both sunrise and sunset
get slightly later each day. Even on the equator, sunrise and
sunset shift several minutes back and forth through the year,
along with solar noon. This effect is plotted by an analemma.
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As sunrise and sunset are calculated from the leading and trailing
edges of the Sun, and not the center; this slightly increases
the duration of "day" relative to "night".
Further, because the light from the Sun is bent by the variable
density of the Earth's atmosphere, the Sun is still seen after
it is below the horizon. This effect is a daily illusion along
with sunrise. As a visual motif, sunset is often associated with
summer, and (particularly when paired with a coconut palm) beach
living and surfing culture. This may be due in the first instance
to people spending more time outdoors in the evening during summer
than during winter, and also because pictures of sunsets over
the sea are often more spectacular than daytime beach scenes (see
images below).
Above Images Are From The NOAA
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