Just a suggestion to layer instead? I don't pull out my ski jacket till it dips below 30 or 35 if there's a wind chill. I prefer to layer.
short sleeve (or sleeveless) cotton tee shirt
Long sleeve cotton turtle neck
medium weight cotton sweater (i can't wear wool but if you can...go with a lightweight wool)
Polar fleece "hoodie"
then a windbreaker or raincoat.
Add gloves, scarf and hat as needed.

This way, depending on the weather that day you can layer as much or as little as you'd like and one (or two) sweater(s), one hoodie and one thin windbreaker take up less room then a bulky ski jacket if folded flat.