I also agree that I feel more strongly about this in the summer months. I wear pants a lot more frequently in the winter. That said, I would rather wear a dress rather than a skirt with hosiery in winter, because I find it annoying sometimes to have two waistbands.
Una: you're right, body type does play a role! I can see that dresses aren't often a great fit with your body type, mainly because a lot of them are designed for my body type (hourglass/pear), which is a big reason why I default to them, and why I find buying pants quite difficult. I'm envious of your lean legs/thighs!