Propagate rose's in the winter?

I have 30+ rose bushes, and my friend has been bugging me for a few years to start her some rose cuttings.  I have been meaning to, but it always seems to pass the right time.
I live in California zone 9b. I was thinking about giving it a try now.  All the bushes still have all their leaves, and a few determined bushes have a flower or two.  I was thinking if I try it now at least they won't fry in the sun, but I wonder if they need a certain amount of warmth?
I have never tried this with rose's before, I tried my hedges last Spring, and they were doing great, until we had an unexpected very hot day.  They must have needed water, or something, because they didn't make it.
Anyway please let me know if you have some knowledge about this subject.  I may try a couple no matter what, but I won't do many unless the consensus is a relatively positive one.  Thanks I look forward to hearing from you.

I am in Z8, and have gotten them to root during the winter. Just keep the humidity high and avoid any extremes in the temperature and you should be fine.
If they're currently dormant, or growing more slowly than usual, it would probably be better to wait until late winter/early spring right before they come out of dormancy or growth rate picks up, but if they are actively growing at the normal pace, they should send out a flush of roots.
The best stems to propagate from are those that just finished blooming, but haven't sent out the post-bloom flush of new growth.
Good luck!