You should be fine with that, Im in Fort Collins, CO and didn't have too much trouble. I could plug mine in most of the time, but when I couldn't I just made sure I left plenty of time for the truck to warm up. I high idle setting is always nice to speed things up.
On a side note..
Im having trouble starting my truck now, but I think the batteries or the electrical system is messed up, its just not cranking fast enough every now and then. Had batteries tested at checkers where I bought them and they told me they were good, then found out alternator was only putting out 12.x volts, so replaced that but still having trouble some days. So maybe batteries got screwed up with bad alternator and are wasted now.