Well, my only experience with Trondheim was about 7 years or so ago. I was deployed aboard the USS Wasp and we anchored out in the bay there. Say about 1 in the am, the wind coming down off the mountains and across the water was so strong, it started pushing a 70,000 ton ship (at anchor, mind you) in towards the ground. We weighed anchor and had to leave because of the weather.
But I heard it was beautiful, the women are HOT. It's a fairly expensive place to live or visit, but the scenery and the women are worth it.
I've also been to Stavangar and Bergen, both for about a day and a half. And both during the winter. Talk about cold. 🙂