Yes, sir...I can see your dilema, Jerry...-10 or -20 is a tad bit colder than I would want to drive our "A" in. I was referring to +20 and up. Ten to twenty below is almost unheard of around these parts. We've seen -10 for a couple of nights in a row every now and then, but nothing like that for any length of time.
Of course...we've also seen temps over 100 for 20+ days in a row, the record being 108 one afternoon. We didn't drive Jippy car then either, by the way...
I have a better understanding of your problem now...and don't envy you, my friend. You keep that kinda cold up there...will ya?