Size question - I'm a skinny 5'11" 135...
Size question - I'm a skinny 5'11" 135 lbs, 30" waist - but would like to have something I can layer underneath for cold (skiing) and something that isn't too floppy for biking. Should I go Med or Small?
Also, how is this jacket for biking - does the fit allow for lower back coverage and are the arms cut to allow good handlebar reach? Does the hood easily fit over a ski or bike helmet?
On the size: with your height you have to go with a medium.
The one thing I would say is with biking you are going to prefer a softshell jacket over this one.
Here are some ideas for what may help you and can also use while you are skiing:
Mountain Hardwear Brono (Sale item)
Mountain Hardwear Android ($78)
I hope you find what you are looking for, and ski hard!