I first noticed this with my outdoor grows, since every grow season is a little different, if we had a cool spring the plants took forever to establish. I guess it slows their metabolisms down, which seems to also slow down their 'inner clock'. They mature more slowly, and can take longer to finish. But like everything, different strains react differently. Some of my outdoor plants seemed to be permanently stunted by cool weather early on, others took off as soon as it warmed up.
I've been keeping an eye on light balance. I think that the warmer it is the faster the metabolism is going, the more light they can process and therefore the closer the lights can be to them. I imagine that at their slower growth rate, they probably need less intense light and less nutes too. Something to keep an eye on, I'm not really sure, it's just my understanding of things.