5/30 in the Enclave, Traverse,CT5 , Elantra. 10/30 in G6 beater
Mine was today -9F. Had Delvac 1 ESP 5w40 3 quarts and 1.5 quart HPL NO VII 5w20 in sump.I think it would be valuable if people also posted what their typical lowest start-up temps of the season are, because "winter" means a lot of different things to a lot of different people.
Last year my coldest winter start was -6 F, and today it was -5.
I run 5W-30. My car specifies 5W-20.