can killing fields finish in norcal?

I'm further south near LA and my Sativas are still in veg. growing outside. I don't expect them to flower until October - November. My buddy on the other hand, he's on his first grow, lives an hour away from me, and he didn't harden his plants off before taking them outside. After a week of being outside they started to flower. It's been around a month since I last paid my friend a visit and they don't appear to be going back into veg. I'm guessing he'll be able to finish sooner, but I should (Cannabis gods willing) have a bigger harvest.

I don't think the strain you have matters. I believe it's how you acclimate your plants to your region.