Is it just because the days are shorter and I'm seeing more sunrises and sunsets or are the sunrises/sunsets in winter more dramatic and colorful for some reason?

I believe, depending upon where you live, its both.

Days are shorter in the winter in the US making it more likely you'll see the sunrise and sunset.

Also, if you live in a cold climate (where the average air temperature is less than 32 F), there will sometimes be an ice haze in the air that relects and refracts the light and magnifies the colours of the sunrise and sunset.

I've always remembered that the colors at sunrise and sunset are more vivid and colorful. And the colder the air temperature, it seems, the more vivid they are.

I did a little research on my own and found that it is actually because the air is more clear at low temps. There is less humidity and this causes the refraction of light to be more vivid.

Thanks for the answers.

Ami - I noticed a long time ago that sunrises and sunsets were much more colorful in the winter. I guess it's because of the reasons that you cited.
Also - I can see a lot more stars than I can in warm weather!

It has seemed, however, that the last few years, shadows have deepened a lot earlier than they have in previous winters...