Well, neither jug froze at -3F last night. Not even a crystal in either one! I expected the RainX 2-n-1 to be OK. The good blue stuff is "SPLASH (r) The Original Blue Windshield Washer Fluid". The jug that froze last year was either sub-standard, or the VOC's evaporated. I forget the brand, but there's no point in shaming them if evaporation is the real issue.
I checked the local Walmart and AAP for Prestone, or any other fluid rated at better than Rainx 2-n-1's -25F. The AAP clerk even checked for me, they had only RainX, Blue, and some 32F stuff. Walmart had only 2-n-1, that I could see, of course no help could be had there.