Winter Sunsets

[virginia17]

In Winter, sunsets and sunrises are brighter and more vivid. Why is this?

[TheFarSide]

One theory is that it's nothing more than an optical illusion. Id est, in winter, natures colours are pale and relatively bland, thus the sun (either rising or setting) appears more vivid. The other (more scientific) reason is that there are far less solid particles in the atmosphere in winter than at any other time of year due to the increased moisture particles. Solid particulates in the atmosphere can increase over 100 times in summer (pollen etc). These act as a 'visual net curtain' between the earth and the sun.

[trilobite]

Could it be anything to do with angle of incidence of the sun?
If we assume 'vivid sunsets' are caused by the sun being at a low angle (and therefore rays of light are passing through a greater thickness of atmosphere) then, during the Winter, the sun is at a low angle for a longer period than in the Summer (In higher latitudes of N. Hemisphere). Would this give the impression of more vivid sunsets as they 'last' longer?

Open to discussion - I was just hypothesising!

[rojash]

Great answers, but who says sunsets and sunrises are more vivid in winter? I've never noticed such a thing.