Normally before i go to the studio, a gig, or to my guitar teacher, I warm up before I start driving there. Normally it's about a 10 minute drive.
Would my fingers be cold by the time i get there?
Probably not, but I would recommend you warm up while there too. A longer warm up at home followed by a short one at the gig might work well for you.
i would stick to your normal plan if they need to be warmed up. i don't know your fingers but they could get warmed up in that time.
I do the same (well, not to gigs as I don't gig yet ) and I always need to warm up again when I get there, although it doesn't take as long as normal.
Unless it is 20 degrees where you live, you will be good warming up at your house than a quick warmup when your there.
my hands, fingers and even feet are always cold.... even while im playing guitar, my hands will be pretty cold.
I only really have to warm up if I'll be playing a different guitar than I'm used to. If I've been playing my SG for 2 weeks straight, and I'm going to practice/gig/record with my Explorer, I will have to run through some of the harder licks to get my fingers to remember them. Other than that I've never really warmed up. Not a bad idea.