I can't say it exactly gets "cold" here but I don't notice a huge difference other than if I'm outside at night or in the early morning (which is no longer necessary as much thankfully) it takes a little longer for my equipment to warm up and provide a satisfying vape. I could see the (vague) possibility that if the VG gets cold it becomes more viscous, and possibly leading to you inhaling a higher percentage of PG at first until your vape warms up? This is TOTALLY speculative, but the two ingredients do behave differently at different temperatures. Maybe try swirling the juice in your tank as you vape if it's very cold?
That's the only thing that kind of makes sense to me, but my older brother is the "smart" one and my little sister is the "pretty" one. I got the "creative" label (these were all from my mom, growing up) so many of my thoughts... Well, it's a thought, anyway.
Anna