I’ve worked up there in the winter, definitely gets cold af. My travels may take me to Chicago, Wisconsin, and possibly Maine/Vermont. I’d rather spend a few bucks now and just never have to worry about having PS issues if it gets down to -30 at some point. This Royal Purple product has a -45f pour point.
Tbh for the price I would go with redline PSF. The royal purple is $12 on amazon for 12 ounces, the redline is $18 for 32oz. Granted you could probably find both for cheaper if you search around.
Cold for me is below zero. i had to change out RL PS because the GM Type II pumps in the 240s squealed terribly at low temps. Full syn DEX VI solved the issue. My coldest start was -17 in Stowe VT. No issues With the PS pump - or anything else for that matter.