Anchie, I suspect this has to do with 1) personal style and color preferences, and 2) climate differences.
1) I am more a fan of deep brights and dark neutrals, so fall/winter dressing appeals to me more. I like prints that are moodier florals and darker color mixes. Deep jewel tones and black, or even charcoal, chocolate brown, and cognac appeal to me more than light neutrals. In spring and summer, the stores seem to fill up with pastels, neons, and light-bright colors that I enjoy seeing but not wearing so much.
I also don't love baring arms and legs so much. And I'm not one of those people who can happily wear long sleeves when it's 90 degrees with 80% humidity, which is the norm here from June through August. It doesn't cool off much at night, and I don't spend my time in massively air conditioned locations, so layering just isn't much of a thing for me in summer. I find summer dressing rather boring: a dress, or a tee and skirt, or a shirt with shorts or crops. No layers, and accessorizing becomes simultaneously more important to add personality but also more minimal because I don't want to wear a lot of jewelry, etc., adding more stuff to contact my skin. In winter, I feel like I can play with silhouette a little more -- bootcut, boyfriend jeans, long over lean, fitted jacket or roomy sweater, layer a big vest over top, choices of long vs short coat or jacket, etc. Plus scarves, hats, and all that...feels like there are more choices. Winter lends itself to more textures in dressing too: leather, chunky or smooth knits, velvet, corduroy, nubby tweeds or wool jackets, etc.
2) I live in a four-season climate on the east coast of the US, but the transitional seasons are sadly short. Winters are getting milder, and summers hotter. It feels like summer drags on here, while winter goes rather quickly, weather-wise. Summers are not just hot but HUMID, and this makes a big difference in the feel of the air. Hot and sticky just makes me feel unattractive no matter what I wear. And there's only so much clothing you can remove when it's hot, you know? In the winter, when I'm cold, I can just put on another layer, or change into a warmer layer!