I have a multidude of top coats. Some top quality and expensive and some more basic and cheaper. Depends on the weather but if it is going to warm up I have a couple that get used more. One is a "Pertex" and the only property this has is that it is windproof. Keep the wind out and you stay warmer. The advantage it has is that it wraps up into a fist size ball to stuff in the rear pocket when it has to come off. I also have a waterproof that is very light and wraps up small. It still breathes and being waterproof- it is also windproof. Then there a couple of coats that are warmer- and pack into their own pouch when not being worn and go round the waist.

But The "Winter" jackets are not lightweight- do not pack up small and just get unzipped if the temp goes up.