|Check out my "normal" opaque tights.|
(Not the best photo - it is hard taking a picture of your legs.)
I discovered Flox tights last year. They are the holy grail - fleecy lined tights. Yes you read that right. Some genius managed to merge tracksuit pants with opaque tights and the result is awesome. They aren't quite as warm as thermal leggings, but they are close and they look exactly like normal opaque tights so no one will know your secret to staying warm.
They do have a slight tendency to pill, so you need to be careful with your handwashing and they do stretch a bit over time - but people, they are fleecy lined tights, they are still awesome.
Apparently this year they are also selling footless tights. This I don't understand. Being someone with perpetually cold feet, why if it is cold you would not want your feet covered is beyond me. But if that is your thing, the option is there.
So if like me, you insist on continuing to wear dresses through winter I highly recommend Flox! You can buy them here on their website.
This review is all my own opinion, I am not in anyway connected with Flox, other than through my now toasty warm legs.