First off, NICE AVATAR! :thumbsup:

Where are you from? If you're in the US, which state?

I think some cold won't hurt them. On my last grow "White Widow Pic", I experimented with some males to see how hardy the cannabis was. I was very surprised how well the plants were growing outside in the low 40's. Next year, try some earlier blooming strains.
I'm trying Early Misty this year. My Misty has been flowering for over a month already and some of my Widows have yet to show sex.
With that much of a difference, you can mature your plants outside.